Filtering AI crawlers at HTTP feels like high-level firewalls, a lot of redoing of the network stack.

Remember when Flash enabled interactive websites? You walk forward with W and peruse the headlines. Press E to grab the newspaper. Piece the tattered pages together. Seven coins for your proof of work.

Those coins are redeemable across certain other sites in a webring?

Although, sounds like a lot of work for a single visit, or onerous for repeat ones.