Maybe the differentiable physics we observe is just an approximation of a lower-level non-differentiable physics, the same way Newtonian mechanics is an approximation of relativity.

If physics is differentiable, that's definitely evidence, by symmetry of is-evidence-for. But I have no idea how strong this evidence is because I don't know the distribution of the physical laws of base-level universes (which is a very confusing issue). Do "most" base-level universes have differentiable physics? We know that even continuous functions "usually" aren't differentiable, but I'm not sure whether that even matters, because I have no idea how it's "decided" which universes exist.

Also, maybe intelligence is less likely to arise in non-differentiable universes. But if so, it's probably just a difference of degree of probability, which would be negligible next to the other issues, which seem like they'd drive the probability to almost exactly 0 or 1.