This comment is absolutely the wrong take on this. For context, Proton Mail was first launched in 2014, and back then, hCaptcha didn't even exist and there wer

This comment is absolutely the wrong take on this. For context, Proton Mail was first launched in 2014, and back then, hCaptcha didn't even exist and there were no other non-broken captcha solutions that worked at scale besides reCaptcha. It wasn't until 2020 that hCaptcha became better known, and until then it was really quite untested at scale. In any case, Proton switched over to hCaptcha soon after but even then, it was not without issues, and did not work for many prospective Proton users. Whether it's reCaptcha or hCaptcha, Proton's implementation always sandboxed it within an iframe which mitigated the privacy concerns and it honestly could have been left like this. But instead, Proton went out of the way, investing substantial resources to build, launch, and operate it's own captcha service. That's actually pretty extreme commitment to the mission, and putting money and resources to prove it.