Looks like the VMU was the primary goal, but it improves the emulators too, as it seems.
Use and objectives
Primarily used to store saved games (save states), configuration files and read-only memories (ROMs). Is scheduled for implementation in the following emulators:
* AES4All: It will allow a better performance of the MMU, making it virtually emulation is fluid, without needing to access the CD reader, which produces a constant slowdown.
* DCastaway: We will use the saved game. Can store items not currently on a permanent basis.
* Gens4all: Items stored and load ROMs.