Regarding game vs. IRL skills, I enjoy Guitar Hero quite a bit, but Rocksmith actually improves your ability to play a real guitar.
Rock Band drums are pretty close to electronic drums though, and vocals are actual vocals.
And as I've mentioned, Ring Fit Adventure (which I'm still playing) kind of levels you up. I found similar effects with Wii Fit, where years after stopping playing (and switching to non-balance based exercises) my sense of balance was surprisingly better than it had been before I started playing the game. I expect other physical games like Dance Dance Revolution are good for physical coordination, and I expect twitch games such as FPSs are good for eye-hand coordination and reaction time.
1) chasing the next thing. Next item, next perfect build, next stat.
2) the multi player aspect. Be it pvp or a coop game with some online “friends”
Both of these are good ways to keep people engaged / addicted I guess.
I definitely think there's value in the second thing, though. Basically, I used to tell people that I play video games "socially" -- until a few months ago (when I decided to actually skill up on Starcraft 2), I almost never played video games unless it was with a group of other people.
There were some fond memories from it, and there were certainly many enjoyable moments. But it was certainly not done in moderation. I'm also glad I pulled out of it, and didn't get into a similar situation with a different game.