Probably wouldn't be a bad idea - however the X0 cap from the DE/Faces LD's from Laserman's broadcast-quality capture equipment probably does a much better job.
USB 2.0 is technically rated at 480 Mbps, slightly faster than FireWire 400's (IEEE 1394a) 400 Mbps. But that's just on paper. In the real world, FireWire 400 transfer rates are still greater than USB 2.0. Google around and you may find some comparisons that can shed some light on why. It probably might have something to to with 1394's peer-to-peer protocol, as opposed to USB's computer-centric, master-slave protocol.
Also, USB 2.0 isn't nearly as well-supported by operating systems as FireWire.