Well, better than if he had done nothing at all..unless you're one of the few who look forward to seeing the world's coastal cities by boat.
Also consider that the film was first and foremost an American phenomenon and in order to inspire anyone to action in this country, you must first alarm and scare the shit out of them. Then they'll get moving.
Aaaaand finally, I know you're probably referring the story about how much energy his house/car/life uses, etc. and that's fine. But some of it was greatly exaggerated, while Gore himself has been trying to address the other concerns (which prompted him to sell his car and buy a hybrid, etc.)
Either way, I don't know how what he's doing is necessarily bad. It's a real concern, global warming, and it's better to work toward a solution than to just sit around making it worse. If he can cause that proactive response, then why not?