Internally, yes, basically a PC in a smallish form factor case.

If you're aiming at the console crowd, upgrades and end-user repairs aren't a primary concern. But you're thinking of it like a desktop aimed at the desktop market where those things are more important, and you could hypothetically just do the same thing on the PC you already have, so what's the point?

For a console the high priority items are being quiet, able to fit in most TV stands and the like without standing out too much, and having the smoothest possible UX - if it's more involved than unpacking it, plugging it into power, plugging it into the TV, connecting a controller, turning it on and logging into an account to go from sitting in a box on the floor to ready to play (or at least install) a game then you've already lost. If installing a game is more complicated than clicking the install button once and waiting for the process to finish, you've already lost. If you are required to fiddle with drivers, settings, tweaks or config files to be able to play, you've already lost. If you are required to think about package managers, libraries, or any kind of usual PC management stuff, you've already lost.