I think resource credit can prevent spamming.
New users have to know that this is not like Facebook or other social media where you can just keep on commenting and posting.
When I first joined, I read first on those FAQ for newbies, dos and don'ts etc.
I'm still watchful on my "resource credit" when I post or comment.
Didn't top-up even once.
RE: Steem's Value vs Newbies's Resources Credits (RC)