There's a functional difference between forcing a crawler to interact with code on your server that wastes its time, and getting it to download your code and run it on its own server - the issue being where the actual CPU/GPU/APU cycles happen. If they happen on your server then it's not benefiting you at all, it's costing you the same amount as just running the cryptominer directly would.

Any halfway intelligent administrator would never allow an automated routine to download and run arbitrary code on their own system, it would be a massive security risk.

My understanding of Anubis is that it just leads the crawler into a never-ending cycle of URLs that just lead to more URLs while containing no information of any value. The code that does this is still installed and running on your server, and is just serving bogus links to the crawler.