Does ecomm create drupal users?

I have set up a generic product and set the anonymous purchasing policy to 'registered only'

What I was hoping is that this would mean when someone goes to checkout and enters their email address, this will then make them a user of my site.

This doesn't seem to happen. In testing this at the moment I am not completing a payment, I go as far as paypal.com then stop. Will a user be created if I successfully complete a payment? Or there's no link between customers and users?