> If they want to keep the signal pure analog, that is enough of a reason.

Why would they want that? It's possible to perfectly reconstruct the original signal. The sampling theorem states that analog and digital audio are equivalent given a high enough sampling rate.

> If a function x(t) contains no frequencies higher than B hertz, then it can be completely determined from its ordinates at a sequence of points spaced less than 1/2B seconds apart.

I don't see the point of analog signals anywhere in the pipeline other than in a DAC whose output drives the actual speakers.