Otherwise a perfect saw would sound exactly the same as any other perfect saw. When people say a certain VCO is fatter sounding or smother sounding or any other descriptor that is used to differentiate one VCO from another, theses distortions are what they are truly talking about. ANY perfectly executed waveform will have the same harmonice, hence the same SOUND and any other perfectly executed waveform of the same shape.I own a mutable instruments braids, and I have to admit, that it is great to have perfect saw, because also the perfect VCO differs from the non perfect VCO by its waveform.
(for those who don't know the braids: it is a digital oscillator, so it can be perfect, but it is voltage controlled)