What he's saying is that it's a bare component. Generally a PC is a usable system.

One will still need to add a powersupply and case at a minimum. (And then you can plug in your power, keyboard/mouse/monitor, etc.)

OK, fair enough. I don't think the lack of a case is a huge deal (zip tie it inside a tiny cardboard box, whatever) but the requirement for a special power supply is significant. In comparison, a raspberry pi can be booted up and used with parts that a typical geek has lying around (micro-usb charger, usb periphs, monitor).

Edit: it looks like it comes with a power adapter, so it's effectively a fully functional computer out of the box (just as much as any system without kb/monitor).