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.
That it would. Granted, a G3 system running classic apps exclusively would be a wonderful ride with MorphOS, heck many MorphOS native apps would still run well, but once you got into web browsing, higher end games and this and that, it would certainly leave a bad taste in one's mouth, at least in this day and age.
Personally, I think I'd rather go with an Efika with a nice Graphics card with plenty of RAM on it, before I went as low as something like an iMac. My eMac was a nightmare within itself!