Had to uninstall it after about one hour. Opening a new window or tab caused Safari to freeze in an unrecoverable state. Force Quit, regardless of how it was invoked, did nothing. CPU usage grew to 100% and stayed pegged there ... forever.
Through the use of the Console and Process Viewer, it seems that there was an application crash (Safari) and CrashReporter would then also crash. That is a huge problem, because you cannot prevent CrashReporter from launching. You can force quit the process, but it automatically respawns in 1 second if there is a crash active on the system. A hard restart is the only way to recover your Mac.

After removing Safari Cookies v1.3.3 via the Safari: Preferences: Safari Cookies panel, Safari once again acts normally.

I don't have any of the Safari add-ons mentioned by the developer as "usual suspects" but I do have two things in Safari that are non-standard: A CSS based ad-blocker and ClickToFlash. I am willing to live without neither, so Safari Cookies must go.