Earlier quoted context omitted.
Great! Lets do the CAPTCHA-test: Will I, as a 100% blind user, be able to complete your process?
I think so? Can you use a smartphone? edit: can't reply, the rate-limiting is such an awful UX
But, I do not have an Android or iOS device as I do not use proprietary software, so a smartphone based solution would not work for me.
Why re-invent the wheel? Invest in making PGP easier and keep the decades of trust building going anchoring humans to a web of trust that long predates human-impersonation-capable AI.