I agree with Sandy, in conclusion, but I have a different reasoning.

The reason why I said Dmax itself is unimportant is because it's rarely used or reached in pictorial images. With my process, if I use glossy surface Dmax of 2.3 to 2.4 is possible but in most images much of important shadow has density of 1.6 or so, and anything beyond that is extra. If the Dmax of the material were significantly lower than 1.6 range, I'd say the image would lack punch because of limited range of tonal expression and/or because an unacceptably low contrast must be used to accomodate the important tonal range to the density range. Users of other processes with inherently lower Dmax may find my view biased or unfair, though...

I have a curve for Velour Black from 1930s in front of me now, but the Dmax is about 1.7. The paper was still considered very good.