I\'ve written tons of operator<<(std::ostream &, const T &) functions -- they\'re incredibly useful.
I\'ve never written an operator
operator>> is useful in converting numbers in text form to an internal representation.
It can also be useful in loading data for objects. Unlike scanf, which cannot be overloaded for different types, objects can overload operator>>. Thus it provides more data hiding for loading objects, the internal representation does not need to be known in order to read data into the object.