Email verification is very similar to https://w3c.github.io/captcha-accessibility/#leveraging-the-multi-device-environment, of course with similar privacy concerns, but many websites that are attempting to limit account registrations to humans require an email anyway, so I think it's a quite useful/effective/accessible strategy in that context.
I do think there's some nuance required to make it effective. Since it's easy & free to obtain new email addresses with services like tempmail.org (or even just adding aliases to a domain you own), some heuristics to score emails are necessary. I suppose https://w3c.github.io/captcha-accessibility/#heuristics covers email in a sense. But I do see a distinction in that there's both heuristics to score the email address and proof that the email address can receive mail.
Email verification is very similar to https://w3c.github.io/captcha-accessibility/#leveraging-the-multi-device-environment, of course with similar privacy concerns, but many websites that are attempting to limit account registrations to humans require an email anyway, so I think it's a quite useful/effective/accessible strategy in that context.
I do think there's some nuance required to make it effective. Since it's easy & free to obtain new email addresses with services like tempmail.org (or even just adding aliases to a domain you own), some heuristics to score emails are necessary. I suppose https://w3c.github.io/captcha-accessibility/#heuristics covers email in a sense. But I do see a distinction in that there's both heuristics to score the email address and proof that the email address can receive mail.