While I understand what you’re saying I think you’ve already lost the average user who probably doesn’t even understand the difference between a web view and opening in mobile safari.
Many sites do similar the idea being similar to a ‘magic link’ when signing into services like slack. Instead of putting in your username and password, you can request a magic link sent via email. When you click on the magic link you’re logged in. The magic link being a tokenized URL.
If you can reset your password with a link sent to your email what’s the difference?