Why overload true and false instead of defining bool operator?

Question

I\'ve been reading about overloading true and false in C#, and I think I understand the basic difference between this and defining a bool operator. The example I see around is

Answer 1

Depending on the system, true can be any non-zero value. In others, it can be any positive value.

Other systems aren't truly boolean, and allow a third state null or nill for the boolean values, which is why you might overload true and false, versus overloading a single bool operator.