Could be because it is less circulated. I had seen the coffee option previously but didn't realise the other 2 options had been setup until I came across this comment.

any particular reason why there are 2 monthly payment options?

Not a YouTube music user but I've started to use the shorts to find new creators since my video feed has gone stale. That's the frustrating since I just want a long form video to leave on but find myself doom scrolling on shorts looking for something new.