I heard of Anubis before a few times around posts surrounding Cloudflare's (CF) efforts around web scrapers previously. Truth be told, I hardly see the Anubis screen pop up. If the site or service is big enough, it would be using CF. If it's small enough or niche, in my mind, it shouldn't have that problem and doesn't need it. I can see big enough niche service and sites getting hit though, and can't pay for CF so they use Anubis. And sometimes those are anime related sites, though that's how I found it in the wild. I think catbox.moe is using anubis, and I think that's where I sometimes encounter it.