Hmm, I remain skeptical. The idea isn't terrible on the face of it, but I would want assurances that they can't get more knowledge about who I am, including get

Hmm, I remain skeptical. The idea isn't terrible on the face of it, but I would want assurances that they can't get more knowledge about who I am, including getting any additional information of the key. I don't care about assurances that they don't do that. The other issue is more practical: few people have such a key (especially when they won't support what is built into computers), and I for one am more likely to solve a captcha, or close the page, than I am to take of my headphones, go to another room and find my jacket to get my fido token. The idea isn't bad, but we need to get to a place where bots aren't bad and that websites can deal with them.