Or "passwordless" login, and I love it. Not many people use password managers and will reuse passwords between websites (I.e. their bank and some random unsecured SaaS product). One-time emailed passwords are an easy way to avoid this problem and have a fairly secure site (mind you, it's only as secure as their email). You can layer 2FA on top of this too.

It's only annoying if the site is constantly timing you out so that every single visit you need to resend. Why not just use secure cookies to remember the user for say a week?