In general, it's neither.
It can add positively or negatively to someone's life.
It can indeed enhance coordination, problem solving skills, reading ability, etc.
It can detract from like when people spend too much time or money on it. But that is a function of the person, I believe, not the hobby itself [some people have addictive personalities, if it weren't gaming it might be baseball cards, alcohol, DVD's, drugs, almost anything.] Or when some 10 year old kid's dumbass parents let him play GTA or Manhunt.
Gaming can turn that idiot box, that vast wasteland, of a television set into a family-bonding experience [last time my parents came to visit, we played Culdcept and Hot Shots Golf Fore, and my dad actually like Ratchet and Clank.]
Making time to game is like anything else, you have to set your priorities and manage your time wisely. I love to play video games, but I rarely if ever play when my son [he's 2] is up and about--my game will always be there, but he's only 2 today.
Gaming is a lot better than a lot of hobbies, and perhaps not as good in some ways as others. For instance, tonight I'm going to go play softball with my city league, then come home and play some video games. Variety is the spice of life, as they say.