Trust me, my team and I often feel at odds with the part that infringes on privacy. As someone that enjoys and wants more privacy, I wish there were other solutions that didn't create a type of dragnet. If it assuages some of your fears, I've never heard of the fingerprinting being sold or used outside of detections.

ALTCHA uses a proof-of-work mechanism to protect your website, apps, APIs, and online services from spam and unwanted content.

Unlike other solutions, ALTCHA’s Captcha alternative is free, open-source and self-hosted, does not use cookies nor fingerprinting, does not track users.

Emphasis are mine. I honestly do not know how this statement is possible. Captcha-less, proof-of-work solutions have to fingerprint on some level. It's essentially having the browser prove it is what it claims to be. I get what they're trying to say but it's marketing. That said, I don't know everything and maybe they have some method I'm not aware of. Grains of salt all around.