Private Access Tokens: Eliminating CAPTCHAs on iPhones and Macs
blog.cloudflare.com
blog.cloudflare.com
I just imagine some video cams with robotic fingers attached to a device and automate browsing this way? sounds viable and there must already be some device farms even with human operators?
hCaptcha's announcement goes into a bit more detail on the tradeoffs: https://www.hcaptcha.com/post/announcing-support-for-private...
The main benefit over traditional hardware attestation is that RSA blinding is used to avoid linkability to a single device.