Never store credit card information locally when using a tokenized gateway
There are two cases in which if you are using a tokenized gateway with WHMCS that you could still be storing credit card information locally instead of at your gateway.
-A new user orders a product and pays with a non credit card gateway such as PayPal.
-They decide they would like to add a credit card to their profile, they do this from the Client Area
-At this point the credit card information isn't tokenized, it is stored locally until the first time the card is used.
-A new user orders a free product and they input credit card details.
-The credit card details are stored locally until the first time the credit card is used.
The underlying issue is WHMCS will only call the storeremote function if the user has at least one invoice set to a credit card gateway.