The common argument is fewer keys means less finger travel means better ergonomics. Hopefully someone with actual experience (i.e. not me) can chime in.
I use Karabiner to create ergonomic combinations on my Mac, and consequently I use my full-size keyboard as if it were a very small one (while awaiting a proper mech keyboard).
And yes, I love having all numbers and symbols at my fingertips without moving my hands. I don’t type faster but I type more comfortably.
I also have the basic editing tools arranged logically so I can move/delete/select a character/word/line at a time, to the left/right. Again without moving my hands.
