I think nothing is a waste of time when you enjoy doing it. To me I think a hobby should be fun and enjoyable, something you can do to relax. It's great if you end up with a usefull skill through your hobby but I don't think that is why should be practicing your hobby. Reading is generally thought of as a 'good' hobby that isn't a waste of time, right? But when you think about it, does a person who reads books (fiction) for a habby end up with more usefull skill than someone who games for a hobby? Not right?