With TouchBar, you cannot change volume quickly without looking at the keyboard, spotlight gets activated all the time as you lay your hands around the keyboard -- yes, it's really that awful for many folk.
A lot of people use MacBook Pros for software development and Terminal access, and F1-F12 keys are often mapped to specific functions, from console software in Terminal, to cross-platform web browsers, to VirtualBox and such. It's not that difficult to remember which Fn key stands for which functions if you're a professional, it's easier to document Fn than the special case of a pictogram that's only available on select hardware, and Fn is 100% backwards-compatible, cross-platform and supported through Terminal OSS applications, plus much faster to use if you're a professional.
If you're a non-professional user who's never used F1-F12? Yes, sure, the TouchBar might be distractingly enjoyable to look at.