[garethadams]

While this will work a very large proportion of the time, and has a big benefit of offloading security as you mention, email is fundamentally asynchronous and can be affected by issues outside of your (and the email providers') control.

Another point that UX designers might make is that this solution necessarily takes users away from your site to complete login, and that can introduce a place for users to drop off. I'm not sure it's that significant, but I've heard it used as an argument.

[vxNsr]

> email is fundamentally asynchronous

Yes, but this affects your recovery attempts as well, today email is basically instantaneous for most people.

> this solution necessarily takes users away from your site to complete login

This is probably the biggest reason to avoid this solution, but I still like it over other options.