This is mainly a Mercurial based question. Specifically Eclipse Mercurial.
After cloning the central repo, making the changes (branch, new feature, merge…), the clone on the desktop is idle and not necessary (it won’t be used again, probably). What should be done with it? Right click, delete?
If the changes have been pushed back to the central repo and you won’t be using it again anytime soon, then yes there is no reason to keep it around.