ProtonMail is said to be privacy friendly email service but some technical issues seem blurry to me. First, it requires JS. Second, its mobile app has to be downloaded from Google Play Store or iOS store. Privacy concerned users might want to ditch Google and similar services entirely.
Third, normally users can do a reCAPTCHA and sign up. But when users try to sign up via Tor network, ProtonMail forces to verify phone number or email address. How does it know whether I am using Tor or not? I suspect IP logging?