If they had had individual keys with screens instead of the Touch Bar I think everyone would have been happy. Have it default to a normal function row but give people the option to customize, let apps customize it behind a modifier key, etc.
But their only usecase that I remember was a touch sliding bar.
I don't know if that would have worked as individual buttons.
The only real function would have been to have customizable icons in that case because you can already assign shortcuts to different functions keys and per app contexts with apps like Hammerspoon
Yes, there was a lot of buzz about a keyboard like that from Art Lebedev* for several years prior to Apple's touch bar.
* https://en.wikipedia.org/wiki/Optimus_Maximus_keyboard