There is a subtle difference :

In #Amethyst , when I fork a note , it is presented to me as a copy , ready for the edit .. which is convenience ..but the crucial thing is there is a (system generated)  link to the original note , which as a user I am abstained from edititing because the link shows up after I already posted ..  I need to check if the link is visible in #gossip .. 

 In a way , I am forced to link new note to  to the original . I guess that is the subtle difference between copy/paste and fork !