Previously as F1-12 Buttons they were overloaded with OS functions such as brightness and audio controls, moving the application Functions to the fn+ combo key.
With the Touch Bar not only are buttons only available when applicable, they also allow for custom inputs such as a range instead of a binary click and their meaning is a lot more explicit with icons and text as opposed to F1-12
I actually think it’s more of a application support problem. If more applications offered better touchbar support I’d be happy about forgetting a series of hot key keystrokes.
I think the target market should be for non-professional users (who don't otherwise use external keyboards and have shortcuts memorized) which is why it's weird that it's a top of the line addition (obviously, a cost issue).