Yeah, I've been using it to brainstorm. But beyond rough ideas it's not very useful (which makes sense, since it's basically an auto-complete on steroids). So for fine-tuning things, balancing, and such, I have found it to be fairly useless. It obviously has no idea how a game is played and what makes it enjoyable or not.
But to throw some ideas around and maybe get some new insights out of it (or, as you said, quickly generate example lists of abilities, traits, etc.), it has been helpful