I hate this workflow. I need to copy-paste the URL from terminal to browser.
Even if I used a webmail, I would need to constantly go there and search for
a new mail every time I'm logging in instead of having the login form filled on
my request.
You are doing this once per device, every n days, with n typically at least 90, possibly more. Your login form consists of a single field for your mail address which is autocompleted. I really do not see your point.
And from the view point of a site owner it's even better: you don't handle passwords anymore. Passwords that many users share among several sites. So you won't be responsible for really, really keeping them secure. Because you don't have them.
Additionally, mail providers and browser vendors have much more security knowledge than pretty much everyone offering a web service.