Why does std::promise::set_value() have two overloads

For the case when std::promise<> is instantiated with a non reference type, why does the set_value() method have two distinct overloads as opposed to one pass by value overload?

so instead of the following two

std::promise::set_value(const Type& value);
std::promise::set_value(Type&& value);

just one

std::promise::set_value(Type value);

This has at least the following two benefits

1. Enable users to move the value into the promise/future when they want, since the API argument is a value type. When copying is not supported it is obvious that the value is going to be copied. Further when the expression being passed into the function is a prvalue it can be completely elided easily by the compiler (especially so in C++17)

2. It conveys the point that the class requires a copy of the value a lot better and succinctly than two overloads which accomplish the same task.

I was making a similar API (as far as ownership is concerned) and I was wondering what benefits the design decision employed by the C++ standard library has as opposed to what I mentioned.

Thanks!