No, FireWire and USB are technologically very different.
While FireWire is a real device interconnection bus, USB is only a PC
-centric polled peripheral connection protocol which is much less flexible and (even with USB2
) much slower than FireWire.
USB 1 theoretically allows 12MBit/s
USB 2 theoretically allows 480MBit/s (in practice much slower)
FireWire also comes in two speeds, 400 or 800MBit/s, but in this case, the speed is actually attainable
So no, you really need that extra FireWire interface for your camera, but FireWire 400 will normally suffice.