In my experience, the biggest issue in numerical/scientific code is to get correct results, these cases will hardly every be caught by typing. Moreover in many scientific programs you deal with well defined inputs, i.e. the chances of e.g. calling a function with an incompatible type are quite low. The most common error I have encountered is a mismatch in dimensionality/shape of input arrays (which I believe isn't straight forward to type for either, in particular if you want the shapes to be flexible, but all inputs to have the same shape).