Now you can add this to your list. You couldn't before.
I mean why now?
or rather, whats the difference between this and memories of phantasm?
This one has full cast of actual professional seiyuus in it making it just professional enough to qualify as anime in MAL's definition, same goes for Summer Day's Dream. Memories of Phantasm on the other hand don't even have any sort dubbing at all let alone a professional one. It's released unvoiced and gets fandubbed. As the whole thing is fanmade it is below MAL standards.
As for why now, probably just because. It's not like it was ever denied before. It's just no one tried to add it before I did. And apparently mods felt like yesterday was good day to approve of something so they did.