Is there any known reason PS3 distinguishes between its standard region mark (1/2/3...), and the relatively rare ALL?
It doesn't mean every language edition of the game is included on disc. While Persona 4 Arena is like the only disc ever to enforce anything.
I've seen ALL on few US games.
Tears to Tiara II
Final Fantasy X/X-2
Tales of Xillia 2
Uncharted (some versions)
Uncharted 2 (some versions)
Uncharted 3