I can't imagine it's anything but a silly comment. Macs have the equivalent of wake-on-LAN, plus you can configure them trivially to restart after power loss. The idea that you'd have to press the button often is just silly.
Given my cat, after learning to press a button on his automated feeder, now presses anything that looks like a button with the curious expectation of food, I can only presume he got out while I was in Cupertino.
Button on the bottom isn't a design mistake. It's an opinionated choice.