The problem is that your shipping method needs your customer delivery address, and your customers will have to login to put their delivery addresss.
My solution would be to :
Allow your customer to buy your goods without registering
.
If you want to have a checkout without registration but with address, you will have to have both "login" and "address" views in the checkout workflow. Then, in the Checkout tab of the configuration, you can change the option "registration" to "no registration" in order to remove the creation of a user account. Also,...