Operator overloading

in this video, sir has overloaded '<<'operator and ‘>>’ operator. But its work is with cin and cout only and they are performing similar function as previous . So what is the new thing in this

new thing is that if don’t overload operators and try to print ll using
cout<<linked_list;
then it will not print list as linked_list is not premitive data type(like int ,float double,char etc)

to print entire list on this statement
we have to overload <<