Even when started reading I still didn't know what it was about. When DJs were mentioned I thought it was something related to turntables, as they are the rotary thing? Vinyl was mentioned in few places so it must be it? Then audiophiles were mentioned which is super strange since audiophiles don't use mixers at all. You're not mixing anything when you listen to music.

Turned out it's just about rotary vs linear potentiometers. Or I misunderstood everything.