@thecarpathian - No worries at all, it is a legitimate question. Aside from code issues, one reason is that a line from the panel is in most cases powering multiple components/devices all of which are probably rated for less than the 20 or 15 amps that trip the breaker, where the magnetic switch/breaker would be rated for the individual piece of equipment.
What I didn’t say is that my amps do not have on/off switches so I actually operate as you suggest, when I want to power down the amps, I walk over two rooms to the panel and throw the breaker or, I can simply unplug them. They probably get powered down about once/month, on average for storms, vacation, etc. They do however have 8 amp (I believe) fuses.
The reasons to consider a magnetic switch/breaker instead of a fuse are reliability, longevity, and supposedly improved sound quality. In the case of my amps, I would need a triple box with spots for two separate magnetic switches, one for each amp, and the duplex that I plug them into. Of course, I would need to split the dedicated 20A line in and then each of the two outlets in the duplex would have to be fed separately from one of the magnetic switches so the amps could individually trip their dedicated switch.
BTW, SMc audio has started using magnetic switches instead of fuses, and they did so on the DAC-2 I received from them last year.