Why should we put inserters in cout

Question

Why can't we use this: cout<<"Hello World"; instead of: cout<<"Hello"<<"World; What is the difference?

Answer 1

Output will differ:
Hello World
vs
HelloWorld
Easy readability is just one viewpoint, it has a bigger chance to make mistakes doing it the second way.

Answer 2

You can by all means do that. The difference is that the former is more efficient and readable.

Answer 3

It the console output operater