Store Currency different from Shipping Currency

I am using OpenCart for a LoyaltyPoints-only store, so I created set the currency in the store as the name "LoyaltyPoints" (instead of USD, etc) since the store is only to sell goods in exchange for LoyaltyPoints.

I still need the users to pay shipping in USD, but under Settings >>Localisation>>>Currency I removed all other currencies because I do not want the upper left hand drop down to display a conversion from USD to LoyaltyPoints (as we do not want to display any USD value).

When my customer goes through checkout, the product is fully paid with points, leaving only the shipping, but the shipping "price" is displaying in the "points currency"

1. Do I have to add back in USD under Settings >>Localisation>>>Currency in order to be able to charge shipping in USD? If so, is there a way to hide the currency translation drop-down in top-left of store?
2. Is there another way to set the currency of shipping as USD?

I have made this module:
https://www.opencart.com/index.php?rout ... n_id=23395
It will allow you to hide it