Anubis remains effective because the token is subject to a rate limit and you could additionally limit token lifetime to some maximum number of requests if you

Anubis remains effective because the token is subject to a rate limit and you could additionally limit token lifetime to some maximum number of requests if you wanted to. All of these factors (total requests, rate of requests, associated IPs, associated browser fingerprints) tie in to detecting bad players, who should receive more frequent and larger challenges.