Because the Switch is a hybrid console, and thus it can be both used as a home console and handheld. So if it can(and is) used as a home console, it competes directly, indirectly, and in any other shape or form against Sony and MS. So comparisons are always warranted, no matter the circunstance.You don't really add anything to this thread but just stating the bleeding obvious. Home consoles have been in decline for years. Japan prefers mobile and handheld. The Switch would never sell anywhere close to these numbers if it were just a home console. I don't know why you try comparing PS5 to Switch when one is twice the price of the other.
PlayStation probably sell more digital games and have a subscription service. Also most of the games are more western oriented.
And Sony's complete failure in Japan has nothing to do with it being a home console. It has everything to do with Sony's incapacity to capture the interest of the japanese market due to not having a hardware and especially software appealing enough for that region.