I think asking for use cases is a very valid question. Methods that end up in an API should have good use cases. I am not saying the ones here don't have them. I would just like to hear your opinion what you think they are. The use cases for arithmetic operations on scala Int are obvious. The uses cases for type-level arithmetics are less obvious. I can come up with rather artificial ones, but do you have one in mind, which you think is realistic in end-user code? (Again, not saying there isn't, just want your opinion).