The whole thing... just make more sense? This is nothing special though, just a regular site but not having a password feels more straightforward.
And what if you lose access to your e-mail? It happened to me a few times and I couldn't log in to various services since their login flow required a 'magic link' sent to my e-mail to login.
There’s also a user experience hurdle where people claim to feel safer with a password or with MFA.
It’s a combination of technical & messaging.