I think the key here is the regret. Is playing games alone, or with friends really that much different from some other activity, such as traveling, alone, or with friends? Sure you learn while traveling, but also get good at gaming the more you do it. You can even substitute traveling with some other hobby (playing the guitar, building legos, etc). Some may argue that the guitar is a "useful" skill but I'd argue that gaming can be a useful skill in the same sense.