Even the smartest people make dumb decisions. Considering how this all went down and how much he tried to get out of it, and how much we're finding out he overpaid for it, I'd say it's pretty safe to call this a dumb move on his part. And I bet if you got him honest enough, he'd say he wished he never did it.
Either doesn't impact me. I technically have a Twitter account which I think I made just to be able to read people's posts. I even stopped that. Never posted anything and I only go there when a link leads there for something else.
I think it all depends on how you use Twitter. If you use it to follow celebs, it's probably pretty benign. If you follow it to reach a community and spread messages, it's a hell hole. If you use it to follow Japanese metal bands, then you won life. If you use it to see how people are talking about things, then you're seeing the worst of humanity.
Either way, it's nothing more than what the people using it make it. If twitter sucks, it's cause the people who use it suck.