I only use it for brightness and volume controls (and TIL about the Emoji picker thanks to a sibling comment). I LOVE the analog-feeling controls on brightness and volume. Even though I know it's the same under the hood as an incrementation button, the UX of it makes me feel substantially happier. I absolutely miss the volume and brightness sliders when I go to use my Chromebook or my wife's laptop.

I normally keep the touchbar configured to only show the ~4 most used buttons (night mode, brightness, volume, and mute), and find that I use the other buttons rarely enough that I forgot what else was on there -- mainly because I use touchpad gestures instead.

I rarely (never?) used F-keys in my IDE (Jetbrains) or other apps, so I don't miss them. I have a physical Esc key (which is nice), though I used it rarely enough on my previous generation touchbar mac that it wasn't very infuriating. Having the physical escape + power keys removed any complaints I previously had about it.