The only difference is that the Asian version of games tends to come with a small instruction card with a game's controls in English. The game itself is still in Japanese. Asian versions of games that are in English often release around the same time they're localized in other countries.
And PSP's dead in the US, so they aren't going to localize it.
It doesn't matter if the PSP is dead. It is being released on the PSN in Japan. There is no reason they couldn't do that here. It would then be playable on the PS Vita.