Same as the Wii though, isn't it?
I don't think going through the digital port on the NTSC is that pricey... at least in my experience. But you would get no 15khz signal. However, who cares -- there are no low-res games on the GC that I can think of, and on the off chance there are, I'm sure they're interlaced anyway. Sucks if you don't a way to view a progressive signal, but this is hardly a travesty. The Wii, on the otherhand, w/ the VC and no low res RGB for NTSC consoles, is another story.