Yes it can backup stuff... It's talking about the connections speeds from the drive to the computer. IE. USB can't do realtime playback of full uncompressed 1080p HD footage.
Other than that it's a normal harddrive... if it'll fit on the drive, then you can back it up on it.
BTW, i exclusively use g-tech HDD's, almost all of their stuff is capable of editing. What drive are u looking at?