This is the basic misconception behind the Anubis design. In an anti-spam system, there's a user/abuser reward asymmetry. Users make single requests and get some constant reward V. Abusers make millions of requests and also get some constant reward V. Proof-of-work exploits the asymmetry: costs are, by a factor of ~millions, disproportionately imposed on abusers.

That's exactly not what happens with scrapers. Scrapers make millions of requests, yes. But each one of those requests produces an average (token-denominated) reward V'. There's no asymmetry at all: you're just adding a fixed cost to each reward, for both users and abusers.

That's before you even get to questions like "does the system actually work, or does a single solve get practically unbounded rewards".

> There's no asymmetry at all: you're just adding a fixed cost to each reward, for both users and abusers.

There is: users solve the PoW once, scrappers solve it every time they rotate IP addresses. Some of them change their IP address on every request, so they keep solving the PoW over and over.

I wonder whether what Anubis is doing might be blocking agents that do not run JS or that have a timeout (or humans who give up as I just did)

I have a small personal site with an exposed Git repository. I'm getting crawled from about 100000 residential IPs from several ASNs (mostly in Brazil). Each crawler makes a couple of requests per minute.

Anubis doesn't really help against this.