Qt uses native controls on Windows or Mac. Not ideally, but it's a viable solution. And it's one of Linux's big two.

Video games count as a damn good reason.

Qt doesn't use native controls, they're lookalike.

The point of the comment asking about Qt is most likely that Qt is not heavyweight (it does a great job even on embedded.), therefore pointing out that there is a difference between Qt and the other you mentioned.

I'm not a fan of OOP and I think there are more interesting framework model - but Qt is definitely the best and most efficient GUI framework I've had the pleasure to work with.