Even with a low power, doing so shows that people are being aware of the fact they are being terrible users, getting a flag out to the right account can help people spot a scam or be hidden to it before sbd or private keys gets lost. Phishers, Memo scammers, and the like are a very serious issue here especially for new comers. Not to mention it makes sense as a community not only to flag bad posters but post about the truly bad and let others know that they need to follow suit especially if your downvote doesnt obliterate them on its own, not everybody has sp like @berniesanders to ruin an account with one downvote.