I agree that bezel size matters but not for the reason you mentioned. When I hold a phone or tablet in landscape mode I need a place to comfortably be able to have a portion of my hand touch without interacting with the screen. The iPhone, iPad and now Google Pixel all have larger bezels at the top and bottom which are perfect for having your thumbs or another part of the hand touch without interacting with the app you are using. This can make reaches into the interactive area a little larger but I think it's worth it to avoid accidental presses which software has been pretty bad about detecting so far.
The iPad Pro is a different beast entirely than the iPhone or the iPad or iPad Mini. I think the use cases are fairly significantly different and so it can make more sense to change bezel sizes and other things about it. That being said I don't find the iPad Pro, in my admittedly somewhat limited use, to be particularly good at detecting accidental presses and so the majority of my use has been with it on a surface.