I think this is a bad idea and will promptly delete any comments stating otherwise.
But seriously, the abuse potential here is clear, and flagging comments is easy enough. This allows users to make irreversible destructive actions which is almost completely unprecedented. I can't think of a single other action a user can take that cannot be reversed. This is why deleting comments is up to the posting user and the commenter; deleting comments is silent and irreversible.
Unlike reverting a good edit to your question, there is practically no evidence of deleting comments (it's hard for even mods to spot deleted comments, it requires manual effort). The system just isn't set up to handle quiet abuse abuse like this; every other change you make is insignificant, reversible and or peer reviewed.
Comments are important for pointing out incorrectness, and it's just too easy to abuse this, even for 10k, 20k, 100k, whatever-k users. Errors in posts should be pointed out, and those comments should not be removed except by mods because of this potential for abuse.