Not really the same thing, but your story reminded me of a long forgotten story.

I remember being in a computer store, and this woman was being told she should buy a 2x SCSI CDR, rather than the 8x IDE one she'd been eyeing (plus controller and cables, etc., of course), "Because SCSI is a much better interface and performs better so the two-speed drive will be faster than the eight".

I couldn't let that go, waited til the sales guy stopped buzzing, and told her the truth of the matter, and showed the specs... 300KB/s versus 1200KB/s has nothing to do with the interface. Yeah, the bus or whatever might be more performant (and do its own controlling, versus offloading), but immaterial.