>>58920384It's not unique to Pokémon, used games are just cheaper in general in Japan. Actually to be honest, pretty much anything used or secondhand is mega cheap over there, both online and in physical shops like BookOFF/HardOFF. If humans hands have touched it once, unless it's a mega rare collectors item, completely mint condition, or has very specific history to it (eg. certain doujins that got cease and desisted by Nintendo, Konami, etc), the price will usually be low. I think it's a cultural thing as I've bought a lot of used books and clothes over there, that are pretty much flawless, but the sellers will always list them as in mid condition unless they're literally still in the original packaging.
God forbid an item has a scratch on it, then they usually sell it as junk/buy at your own risk