If one disregards the local contrast say in a film curve, if it is concave or convex, or both. If we go from the toe to the highlights on a pronounced S-curve the grey tones should be expanded giving more grey tones. On a straight line the tones are contracted.
I am not saying one is better than another. It is of course impoertant what paper we use and how we enlarge the picture if hard or soft.
Just the distribution of the tones on the film curve. I would say a "modern" straight line gives us superior local contrast while a "old" film gives us more grey, softer shaows and lights but an increased contrast in the mid tones.
This comes back a bit to the four quadrant reproduction curve graphs.