Well Button has done the most overtakes this year and has not hit anyone while doing so, which shows he is not the cautious driver people lable him as and also that you can overtake a lot without crashing.
I think Button is cautious in a way, perhaps watchful is a better word. His judgement is unparalleled, if the move isn't there to be made he doesn't force it like others might. I've said it before and I'll say it again now: for me, his racecraft is better than anyone else, he's ruthless with his overtaking, clean in defence and he doesn't make mistakes.