Twitter is like the 15th social network, and even amongst those who use it, a lot (adults who use it as marketing tool) wouldn't use grok anyway. If I had to guess who is a regular user: a male in the US (not necessarily born there), between 13 and 25, either still a student or in an internship, probably a fan of tech and/or Musk.
None of the three people I know use AI at all, so that clearly gives me a good insight into AI usage. /s