Active vandals with evil names are often caught and reverted by local admins and rc-watchers before they are hidden. The resulting reverts, if done in the standard way, include the name in their edit summaries:
After a successful lock and hide, even if resulting edits are deleted from the article history, not only does the name still appear in these histories via the rv's, but it is now harder for local admins to track down all edits by an active spammer or vandal to clean up those ripple-effect edits.
A change to the extension could look for instances of the name to be hidden near the user's edits and offer appropriate action (for instance deleting both the edit and its rv). This would be easier to script if bug #7566 were resolved.
See Also: T23612: Remove username from LQT titles