The concept of "smooth" is fairly rooted in reality, right? This is one of the concepts that a continuous set of numbers like the Real Numbers can accommodate: https://en.wikipedia.org/wiki/Smoothness
If it turns out that reality is actually jagged at the quantum scale that doesn't mean that our conception of "smooth" is void.
Exactly so. When reality becomes too complex, we abstract some things away to get a simpler model. (This we "forget" about the finite and get infinity; ignore the jaggedness and get smoothness).
