I don't know about "use" — luckily, there's no opt-out telemetry — but enough of "enthusiast distribution" users who have also opted in (very biased sample) have explicitly installed zsh (not necessarily run it)
https://pkgstats.archlinux.de/compare/packages#packages=bash...
OTOH, it's only 4-7% on Debian (also opt-in):
Why does this type of statistic require an opt-in solution? Can't the Arch mirrors just tally requests for each package without identifying information like IP adddress?
Maybe they can’t ask for info on every mirror.
I use zsh at work and bash at home. I am such an unsophisticated user that I haven't noticed a real difference! Other than I can install ohmyzsh on zsh.
I repeat the different variations of the same command so often that I get a large quality of life improvement by making that easier- that's why I take the trouble to install zsh.