We do a lot of Thai, Chinese, Indian, etc when we eat out, and while I believe I've seen children's menus at some of these places, I don't think that we've ever ordered off them. I make sure to order a few things that everybody likes and we share.
There is one pub-type burger/pizza/sandwiches place we go that does have a children's menu - I like it because the portions are more what the kids will eat, and there are more side options than fries or salad (can get applesauce or fresh veggies).
I do like kids menus for the smaller portions and smaller prices.