What for? I don't know a single F key shortcut. People say debugging, which seems fair enough. I guess I've always found the mouse-based controls sufficient to use the Xcode debugger.
Apart from the debugger, what do people need the F keys for? Are people really debugging that often?
I use a hell of a lot of keyboard shortcuts, mind you. But none of them are F keys.
A pianist that doesn't use some keys is limited in the music they can produce.
I can write exactly the same code as you without using shortcuts.
I think the advantage is that I don't have to learn completely arbitrary lists of silly little keys to press, and I can keep my brain-space for useful things.
Respectfully, the point of keyboard shortcuts is that they are remembered in your hands, not in your brain. This is the main reason most of these commenters reject the Touch Bar: lacking tactile feedback for button position, it seems like it would be difficult to develop "muscle memory" for a Touch Bar function key.
Apart from the debugger, what do people need the F keys for? Are people really debugging that often?
I use a hell of a lot of keyboard shortcuts, mind you. But none of them are F keys.