Now, for an analogue signal, the accuracy is perfect, the sound isn't
said
to be 'to the nearest x'.
Nice theory but how does that work in practice?
Don't analogue signals suffer all sorts of atenuation and distortion
once you attempt to propogate them?

Yes, but that lowers the precision of the signal, not the accuracy. The two
are not the same.

I suppose you could argue that a record is 'to
the nearest atom of vinyl'
Only if the "resolution" of the mastering process is at an atomic level
and if you start to examine vinyl at an atomic level the actual playing
of the record will alter the shape of the groove simply because of
difference of the physical properties of diamond and vinyl.

That's why I went on to say "accuracy on that level is pretty much
irrelevent", It remains that the axiom of a vinyl recording is the atom.

--
Jim H