It's there to make your life easier. Understand the power of that overloaded operator.
The << and >> are bitwise operators known as the left-shift and right-shift operators.
By overloading these operators, you could have constructs such as the following:
You could write your own classes that overload the << or >> operators , then you could use it with cout, or cin, or even with a file, eg.
cout << object << " " << ival << " " << dval;
But why were the << and >> used for cin, cout etc?
ofile << object;
Well, can you think of a better operator?