As an oldster, I've watched a few to see what the kids are up to. In some cases, the listener was an expert and added to my knowledge and appreciation. In other videos, the listener was simply an outsider (usually a Black person listening to classic rock), and while I didn't learn anything, it was heartening to see someone discover and appreciate new (to them) music.

Still, I would like to see reaction videos about "Prokofiev or Evan Parker or Albert Ayler." In the meantime, I'll just post my own lists of obscure musicians here and enjoy the comments of Riff listeners.