Whatever happened to Privacy Pass? I seem to recall it being touted as the solution for maintaining privacy but keeping bot traffic out, but I haven't heard any

Whatever happened to Privacy Pass? I seem to recall it being touted as the solution for maintaining privacy but keeping bot traffic out, but I haven't heard anything about it in probably five years or so. I'm also not understanding how enabling Tor routing prevents bot traffic from hitting the site. The traffic gets served over a .onion instead, cool. But how does that prevent the bots?