The placement of the switch made me first believe SD had a plan or an idea of using a logic power button on the front while the switch was a mechanical main power switch.
But I was wrong.
When I first saw photos of the new MixPres I assumed that the power switch
was that SD logo button, & that it followed the common "press-in & hold for 2 seconds" logic. So I was a bit surprised that the actual design was so fiddly. But it is still a logic switch, which requests the system to shutdown. This is a nice feature which prevents accidental power down if, say, the machine is still writing to the card when you flick the switch.
Not that "flick" is the best term for: "Take out your flashlight & peer into that dark corner. Using a toothpick or specially maintained fingernail, align with the grooves on the switch and actuate." lol
But this and the misplaced h/p encoder knob are minor niggles in an otherwise solid machine.
I've since stopped worrying about the power switch on the basis that, once you know your power pack run-time, it's not something which needs to be accessed very often.
And don't forget, you'll never inadvertently power down because you brushed against it!