Staff, mods, admins, have other tasks to work on based on reports, they don't have time to check every post/topic and every board.
I don't know how many mods there are on the forum (I'm sure I could figure it out, but I'm too lazy for the purpose of this post), but given how many sections there are and how many posts get made in each of them every single day, there's no way in hell they'd be able to detect spam, zero-value, trolling, or off-topic posts; make judgements on those posts; and then take action if it weren't for members reporting posts like that.
On other, smaller forums, things might work differently--but bitcointalk has many thousands of active accounts and well over a million registered ones, active or inactive. Theymos would have to hire a small country of moderators if he expected them to sift through threads looking for rule violations, and he's not about to do that.
If I remember correctly theymos said a while back that coding badges in such a way so that people could have the option to display or not display the badge would be difficult.
I don't believe that for a minute--even though I'm not a coder. If those gold coins can be put under every member's rank, I seriously doubt Theymos (who is very intelligent and has a lot of resources) wouldn't be able to give members some sort of badge. Plus he did exactly that for the forum anniversary art contest winner if I'm not mistaken.