One could argue that the interesting parts of simulation require higher precision. When you are in stable conditions, that's where your intuition might be sufficient already; once you hit those ugly parts then you start requiring as high precision as you can get to have any correlation with reality. Even a simple solar system simulation through gravity interactions has significant drifts in FP64.

Datatype requirements vary in time and space for a given application. We're just beginning to optimize for this, so there is yet much to discover.