Passwordless authentication: Secure, simple, and fast to deploy
At my company we've been using this technique for years.  Users have always hated it and after waiting a long time for people to come around, we are now transitioning back to traditional login mechanisms.The basic reasons users hated it was that a login mechanism needs to be reliable.  In particular, we make business software, so if the user was ever unable to get into the system it was a big problem.While it may seem that you "always" have access to your email, or sms.  Not all users (especially non-technical users) always have access to these things.  Meaning, even if they have access 98% of the time, that other 2% of the time infuriates them.It was also a usability nightmare among non-technical users.  Traditional login mechanisms dont necessarily mean a more usable experience, but its a pattern that everyone knows.I think login mechanisms on the web can be improved, but not like this.  As someone who has a lot of experience with this, I strongly recommend against it.