It's a dev kit, not a retail product. Do you think that the PS5 dev kit looks premium?
It is a prototype not a devkit from what is on the OP.
It has a port specifically for a diagnostic tool. That screams dev kit to me. A random person wouldn't have access to a prototype of final retail hardware in order to leak a picture of it, it would have to be somebody who worked at MS, and I doubt anybody there is foolish enough to leak a picture with the serial number visible. On the other hand, there are lots of Xbox Series X dev kits out in the wild now and it would be much easier for somebody to get access to one of those to take a picture of it, and Xbox dev kits look alot like the retail design usually. But either way it doesn't really matter, it's not a finalized design. Changes will be made, there are rumors that MS is considering USB-C instead of A on the final model, material quality could change, the removable back might not make it into the retail model, etc.