[bee_rider]

Maybe it depends on the application?

If you have written a linear system solver, you might prefer to express yourself in terms of single/double precision. The user is responsible for knowing if their matrix can be represented in single precision (whatever that means, it is their matrix and their hardware after all), how well conditioned it is, all that stuff. You might rather care that you are working in single precision, and that there exists a double precision (with, it is assumed, hardware support, because GPUs can’t hurt us if we pretend they don’t exist) to do iterative refinement in if you need to.