I think the issue is that many sites are too aggressive with it. Anubis can be configured to only ask for challenges if the site is under unusual load, for instance when a botnet it’s actually ddosing the site. That’s when it shines.

Making it constantly ask for challenges when the service is not under attack is just a massive waste of energy. And many sites just enable it constantly because they can defer bot pings from their logs that way. That’s for instance what op is doing. It’s just a big misunderstanding of the tool.