This model works great when the vast majority of the interaction on your site has no need for a persisted session. If you can provide your value with an unauth

This model works great when the vast majority of the interaction on your site has no need for a persisted session. If you can provide your value with an unauthenticated session (which is different than no session at all) most of the time, but only relatively rarely need an authenticated/non-volatile session then by all means try this. Of course if you do try it, you still want to give users the option of a password authentication versus email link. Step 1 enter email, Step 2 enter password or click button to get a code. But I think if more than 10% of the active sessions on your site are authenticated right now, don't bother with this.