Significance of WebGetAttribute over WebInvokeAttribute

Question

I am trying my hand on RESTful WCF service. to make a method callable using REST, we decorate the method with WebGet/WebInvoke attribute along with operation contract.

 

WebGet is similar to WebInvoke in all manner except Method parameter. According to my understanding when we use WebGet, http GET method is used. while using WebInvoke, we have liberty to use any http methods(GET,PUT,POST,DELETE). If we can fulfill all our needs through WebInvoke, then why WebGet is there ? please satisfy my curiosity. Thanks.