All the royale games are popular enough that high level accounts can be sold for sizeable chunks of money quite easily.

I know some people in the middle east who even do it as a side "job" since the pay is significant enough

pokemon go is a much more "visible" game. if you have any idea how the game works, it's really obvious when you see people playing it irl. it's hard to notice people playing clash royale unless you look at their screen or hear them talking about specific cards from the game. when I was waiting for a flight at the airport recently, almost all the kids seemed to be playing clash royale.

anecdotally, I don't notice clash royale being as popular with adults as pokemon go. it may be true that it's not very popular in your world, if you don't spend a lot of time around children/teenagers. in my bubble, I hardly ever see people playing pokemon go anymore.