Imho, a good type system for scientific computing will let you check that your computations are well formed. For instance, if one tries to apply a matrix to a vector of the wrong size, the type system should report it, or rather one should be able to express this sort of constraint using the type system to the same effect.

You are however correct, that doesn't mean that C cannot be useful for scientific computing, but I think that there are better alternatives. Although, one can write the core functionalities in C for speed and efficiency, and use another language as a driver.