Is there a design reason why std::set doesnt have front and back member functions?

1. I know I can use *s.begin(), but same argument can be used for vector, which has front/back
2. often I use the ordered property of set/map to get "smallest" element/key - ofc the fact that I do it is not the reason to have it, just a example :)

Here I'm talking about design reasons why front/back would be bad design, so please skip obvious reasons like committee forgot about it...