Hi Wayne, in what situations are you getting a speed improvement? I didn't get much of a difference doing a couple tests with either "normal" exports or "using quicktime conversion." I'm on FCP 6 though ... not sure if it matters.
I'm not 100% sure this is only a FCP 7 thing or not. But, outputting ProRes422 and XDCAM HD sequences seem to output much much faster for myself.
Besides, you can output more than one sequence at a time doing this... Some of us end up with multiple versions of a program and we need to keep shelf masters of each. Exporting all of the sequences at one time makes more sense.