Exactly. As I said, even the 400/500MHz Pismo G3 is only just sufficient to run OSX 10.4 and barely handles TenFourFox, but by Amiga standards that's downright luxurious. Add in the fact that these go for a good deal cheaper than the G4s, and I think they'd be perfectly decent MorphOS machines...
it's somewhere on their website, but basically, it'd make bad impressions of the OS, if people ran it on less than a G4.