I've been using this for quite a long time. The main selling point is to filter out search results, and it does it fine; it doesn't prevent access to the site by e.g. manually typing the URL. For the later, as another poster said, uBlock Origin works better.
(Funnily enough I installed it because of Reddit. When I want an answer I want an answer, not a bunch of parrots repeating the same stale jokes, the same "I dun unrurrstand", vomiting trivia or crap like this.)