Are we playing with an idea that has similar dangers here? Ask the opposite question: what would happen if typeface designers didn't go to all this detail? Would we just want to know that "Arial is the round-ish one and Times New Roman has little footsy things?"
Font selection is a big deal to brand identity and marketing. They like to have lots of choices. We even design our own fonts sometimes. How many developers have, as I have, changed fonts in our code editors, looking for the one that's "just right?"
For whatever reasons, the demand for distinct fonts is high, and if there are lots of fonts, they need to be completely specified, so that they can be created and rendered correctly.