I can't answer your question. I can answer only your comment about seeing no reason why people want quick access to change the ringtone volume -- as I totally want quick access to change the ringtone volume.
At work, the phone is at my desk, about two feet my face, and a wall away from my boss. I turn my ringtone volume down when I get to work -- so that I can hear it, but nobody else can.
When I get home, though, the phone stays put while I move around -- so I want the ringtone louder, so I'll hear it.
Different volume in the car, too.
So, basically, yeah, I am constantly changing my ringtone volume and like the easy access. (OTOH, I always listen to music through earphones, so my media volume is generally constant. To the extent I need to change it due to ambient noise, I do that once I start listening.)