Why should it be used on anything at all? One of the things that you can also do use your power to flag posts you think violate community standards. I did that on a post I resteemed after I realized it (allegedly) committed copyright infringement: https://steemit.com/photography/@olivia0001/humming-bird-in-rain#@joshpeterson/re-olivia0001-humming-bird-in-rain-20170905t233025847z
If you click through the link, you'll see that I also commented to make my case as to why I flagged the post so someone looking through the blockchain at my user history can see it wasn't a frivolous action.
If you're worried about spammers "scamming" the platform, again, the rate limiting mechanism of Steemit and Steem already account for that. Voting and posting power is limited per day. And because of the ability to flag content, the community is self-policing.
Kind of to reiterate @kxp's suggestion: did you read the whitepaper? I think that will help answer a lot of your questions.
Also, what brought you to Steemit? Happy to have you here. :)