I automatically assume I'm in an adversarial position vs such a thing and don't care what kinda shit they try to pull - they're met with the full arsenal of privacy enhancing tools at my disposal.
as for me, an email provider that asks for no backup email or other verification methods can come useful in everyday life, thanks for mentioning them.
don't like the email domain, the UX is nothing to write home about, and they're obnoxious with the upsale pitch, but with a few tweaks here and there this can be useful for signups, transactional emails, and the like.