Don't buy it. It's most likely a hacking device that tampers with your system to allow forced full game installs. And a perma-ban as well.
I don't know why people obsess over forcing game installs like the otherbox does. The normal install is OK, because it allows developers to stream low-intensity data from the BD disc, then more intensive data from the hard disk (LBP2, Battlefield 3 and God of War 3 does this).
It's a case of "they have it, why don't we?". And I really believe that some what the exact same features across the board, that way there's no difference between the two systems.
The reason to have this could for an example be that i am tired of playing Skyrim with lag. I dont know if it would help if i could install the game completely but it would be worth a shot if it wont mess up my ps3
Skyrim installs the game completely to the hard disk. In fact, the Blu-ray drive powers down completely after you start a game.
For me, Skyrim plays smoothly, but only after slapping on a 7200RPM, 750GB hard disk on my old 80GB PS3.