I've played video games since I was a kid and I still play, but I don't feel that I have the control using my thumbs that I do using the pinch method. I have better fine control, but I find myself more and more using my thumb on top with my finger on the front for support. Seems to evolve as I do different things. I know that when I fly helicopters I definitely use pinch more than thumbs. With planes I seem to be more relaxed and more likely to use my thumb.
I have also noticed though, that when I use other people's tx's who fly with their thumbs, they have the sticks as short as they will go like a game controller. I have my sticks as long as they can go more light flight controls. It's very difficult to fly my tx with your thumbs unless you have huge ape hands like I do. At least that's what my friends tell me.