I remember reading something Randall Smith (Mesa/Boogie) wrote years ago about the standby switch, where he said essentially the same thing but that players in gigging bands would still want it to mute the amp between sets so they can keep the thing warm, so makers keep putting them in. Sounds reasonable to me - I still want them for that reason because I don't want to be messing around with the volume to take a break once I get it dialed in.