So is any Android phone in such case. Form factor matters.
The Deck is a Linux handheld, that can be converted to a Linux PC depending on the accessories used. But by itself, with no accessories whatsoever, good luck using it as a PC.
A laptop can be considered as a PC, as it has all the peripheral integrated into his chassis, a desktop too (as it cannot be used without peripherals, they can be counted as part of it), but a Deck primary use is handheld gaming, not personal computing. Its included peripherals cannot allow it use as such.