I think where the 2.5" to 3.5" SATA drive converter fits in is where you need a 3.5" drive but what to use a 2.5" drive. Not just mounting a 2.5" drive but require a 3.5" drive. Such as in a server with hot-swappable 3.5" drives but you want to put in some 2.5" SSDs or something. So more like buying a WD Velociraptor mounting kit by itself. A generic adapter plate won't line up the connectors correctly and many times don't have the holes in the right place. This will.

Any idea if the USB to SATA supports UASP?