Speaking as someone that switches methods I found that since I started out with thumbs only it was hard to switch to the "pinch" method. I found out by switching that I had more precise control but it took a while. For competition I fly pinch and for everyday sport flying I use my thumbs. I do use a tray when I fly pinch so I do not have to hold the TX and can rest my wrists on the sides of the tray.

And not to start an argument, not all the top pilots fly the pinch method, Chip Hyde uses his thumbs as does QQ, Bill Hempel, Jason Shulman switches and quite a few others fly thumbs. I've spoken to all of them at different times on this subject and they all agree to fly the way you feel comfortable.

I also have found that teaching someone who flies the pinch method does take a bit longer as they usually have a harder time finding a good position for their wrists until I give them a spare transmitter tray I have then it becomes a bit easier since they are not holding onto the radio any longer. Most end up buying/making a tray and for me using a tray while flying thumbs is next to impossible