Why do we need anything more than HTTP GET, PUT, POST?

Question

What is the practical benefit of using HTTP GET, PUT, DELETE, POST, HEAD? Why not focus on their behavioral benefits (safety and idempotency), forgetting their names, and use GE

Answer 1

There are http extensions like WebDAV that require additional functionally.

http://en.wikipedia.org/wiki/WebDAV

Answer 2

To limit ambiguity which will allow for better/easier reuse of our simple REST apis.