I got a pocketstation a while back. While it's nowhere as integral for most PS1 games as the VMU was for Dreamcast games. It does have some neat or soulful uses, and even whole games dedicated to it. Pocket MuuMuu, a jumping flash spinoff, has more than a hundred downloadable minigames and tools that you can buy with points you get from playing other minigames, Pocket Digimon World lets you turn your PocketStation into a glorified v-pet with up to 6 digimon on the same device, with features like an adventure mode, battles or jogress evolution with another user through infrared, and even a Pokemon-Stadium style colosseum in the PS1 disc. Brightis, FF8 and some other RPGs have minigames that can level up or upgrade your in-game characters or gain items, essentially just giving you a fun way to grind on the go. There was also some Yu-Gi-Oh! game that infamously became a lot grindier because of some PocketStation feature for unlocking cards that didn't make it to the western version.
Thankfully PocketStations themselves aren't region locked so you can use them on burger or yurop systems just as long as they're modded to play japanese games, or the few burger localizations that left pocketstation support like RR4 or FF8. There's also patches for games like Digimon World 2 or Legend of Mana that add pocketstation features back into their US versions.