For a standalone Pi power via USB is fine. As soon as these devices get embedded or you're running more than two in proximity the USB spaghetti gets pretty miserable.

There are so many quirks with the Raspberry Pi that make it a pain to work with, from the lack of mainline Linux support on the Pi 5 to the awkward by default power arrangement to the fact that the architecture is a GPU with a CPU glued onto the side. The Raspberry foundation made SBCs much more ergonomic and kudos to them but working with them still feels like walking through a field of tiny rakes.