What are the uses of the type `std::nullptr_t`?

Question

I learned that nullptr, in addition to being convertible to any pointer type (but not to any integral type) also has its own type std::nullptr_t. S

Answer 1

Also, what other type would you give it, that doesn't simply re-introduce the problems we had with NULL? The whole point is to get rid of the nasty implicit conversions, but we can't actually change behaviour of old programs so here we are.