For most people, the answer is likely to be "Yes, but only occasionally." All the the sports are extremely simple, but also extremely polished. And they are ideal demonstrations of what the Wiimote accelerometer can do. So I find myself loading the game when I want to spend a few minutes relaxing or to show off the Wii to friends. But none of the games are going to suck you in for hours at a time.
In tennis you always play doubles. You can chose to control any number of players including none (for a demo mode game) and all four. Actually, you don't control the player—just their rackets. The onscreen players rush around on their own to get close to the ball and you swing the Wiimote at just the right moment to swing the onscreen rackets. All the players you control swing at the same time, which is odd, but not really an issue once you get used to it. Virtually any motion that is vaguely like swinging will be detected as a swing, so it's possible to play while sitting on the couch. But I recommend always playing standing, since it feels a lot more like tennis and less like a video game that way. This advice holds for all the other sports as well.
If there were nothing more, I'd probably be done playing Wii Sports tennis permanently. But there are little nuances that encourage you to come back once and a while. There's a power serve if you swing fast enough at just the right moment. Good timing on the return can help you place the ball in a location the other team can never touch. Twisting the Wiimote gives the ball spin and altering the angle of swing produces slices and lobs. With practice, you can become a master of this very basic tennis simulation. It's probably the sport I'm most drawn to in the package.
Baseball is a perfect illustration of the strengths and weaknesses of Wii Sports. For the casual fan, this will eliminate any need to buy a full-fledged baseball game. The pitcher has four pitches to chose from and can throw harder and softer with faster and slower throwing motions. Batting is mostly a matter of timing and swing speed. Once the ball is hit, the Mii players hop around like Larry the cucumber. There are no throws—balls hit in the infield magically produce outs. Human players have no control over base-running or fielding, so the game is purely based on the pitcher/batter match-up. Fun but not deep.
For more serious fans of the game, the shallowness of the experience gets old quickly. Every pitcher has exactly the same abilities and the number nine hitter is just as likely to go deep as the Mii batting cleanup. While the act of pitching and batting with the Wiimote is visceral and natural, almost all pitches are strikes and can be hit deep with a bit of practice. It's fun and cute to play with your family represented by Miis, but you can't set teams or lineups beyond the lead-off hitter (your Mii) and pitcher (you again). Since there is no baseball strategy, I suppose it doesn't matter. For a fan, Wii Sports baseball is a shadow of the true sport.
Clearly the crown jewel of the collection. No doubt there are some affectionados would prefer a simulation that includes differing equipment, PBA tours and championships, sponsors, customizable lanes and oil patterns, online leader boards and so on. But, even true fans would probably want a game built around the simple and effective mechanics of Wii Sports bowling. There's a reason the Wii is sometimes called The Bowling Machine.
It is not possible to play bowling by randomly wiggling the Wiimote, unlike the other games. (This has been scientifically proven by my 5-year-old son shortly before bedtime.) You have to actually press buttons and simulate a bowling motion in order to roll the ball down the lane. Initially, aiming a shot square at the head pin seems the best strategy, but right handers will find the ball naturally curves to the left side of the lane. Lefties will tend to curve to the right. This happens because the motion of bowling usually causes a slight twist of the wrist, which is detected by the Wiimote and translates into ball spin in the game. The problem can be corrected by stepping to one side or by resisting the tendency to induce spin. With practice, it's possible to spin the ball in either direction with varying speed. Release point also matters: release high enough and the spin will not have time to alter the ball's path.
I hate to say it, but Wii Sports bowling has almost all of the good features of a night at the local alley, but none of the bad. For the price of a Wii, you can bowl as many frames from the comfort of your own home as you care to bowl. No smokers, crappy balls, ugly shoes, greasy food, drunks, league nights, pinsetter malfunctions, and so on. My family probably will go out for bowling again at some point, but there's no hurry.
Again, Wii Sports captured the essence of golf without going into great depth. As a non-golfer, I found the swinging and putting controls a reasonable facsimile of how I'd swing a club (if I did). True golf fans will want to get a more extensive game, however. Unfortunately, the rest of us will get bored with this game as well. The courses are gorgeous (easily the most impressive graphics in the package), but they are static. You can't download or design new holes, so the nine that come with the game will be all you will ever get. Even though I have resisted playing golf more than a few times, I'm a bit tired of the courses.
I do like the way the game plays, but since none of my family is excited about it and the holes remain the same, I don't play it much. My guess is that in the future I'll play it in order to get to "Pro Level" in all 5 sports. Ideally, the nine holes will be like old friends that I'm comfortable with because they are old friends. I'll let you know.
The only sport that uses the Nunchuk also is the only sport that isn't completely natural to play. Presumably the idea was to have both controllers behave as if they were fists, but somehow it doesn't always work out. Too often, a punching motion is not recognized by the game and your onscreen fist just floats uselessly. Wild shaking of the controllers seem sufficient against week opponents, but as you climb the skill ladder, you will reach a boxer who will block or avoid your flailing gloves. I'm convinced there is a skill to master, but I don't yet have the knack.
One of the true strengths of the boxing game is that it can be a decent workout if you take it seriously. Unlike real sparing, your partner can't physically damage you. After a few rounds, your arms will be ready for a break. No doubt, this sport was part of the inspiration for the development of Wii Fit (though the later is more comprehensive).
Training and Wii Fitness
Speaking of a workout, each mode has three training mini-games that drill you on various skills needed to be successful in the full games. Also, there is a fitness test that challenges you to three training sessions and rates you. Although the games use the same controls as the full sport, there is something refreshingly different in training. Even golf is more entertaining in this mode. One secret to replay values, as silly as it seems, is the fitness test. Since it only can be done once a day, I find myself tacking it onto the end of a play session, even if I was playing another game. It's surprisingly addictive to see my "Fitness Age" rise and fall as I am challenged with different training modes.