I'm sure it was just an oversight, but you really did mean to start your reply with some kind of "thank you", right?
I feel that the <CLEAR> button is "best used" for exactly what it does now. The package is open-source, and an easy-to-edit python script. If you are of the opinion that something is a "must-have", then make the change. Personally, I don't want to clear numbers from the history list (and that's actually more difficult than it seems). The history list is stored in a file: /home/user/.gcdialerhist, which lists the number called and a timestamp.