Valid point to be honest, but the answer is probably more than you think. I have a PC and still used the Steam Deck to browse the web too, not at least to install stuff. Also searching something while playing is useful too. Its made to be docked to bigger screen as well.

While you are probably right, my point was its still a PC, because he compared it to Android. And why this is hugely different. His point was to exclude Steam Deck, because it is not a PC, just like we would exclude Android. This data from the stats probably does not make a difference if its a Steam Deck or not (nor can it tell it? because browsing is the same as on PC, its an Archlinux and regular browser after all). On the other side it can definitely tell if its Android and exclude it.

So regardless if you think people browse the web with Steam Deck or not, this data should not be able to tell the difference between most distributions and Steam Deck, as its just a normal PC with Firefox (or other web browser) from the point of the stats. Just my assumption.