Many are. But I've been in more than a few that resulted in discussion that ultimately saved many many hours of time that would otherwise have been spent on something that wasn't necessary.

Actually the only thing I dislike about stand-up is struggling to remember everything I did the previous day, then realising I've forgotten to mention one or two key things after the meeting's ended, and wondering what everyone thought about the fact I apparently did so little... (which is silly, I know, but we're all human).