The problem is having such a system elsewhere for use just in transaction rather reporting to your bank or not, cause so to say as card use, you wouldnt have to, unless using as say a "credit" card for your funds or credits. Money. Cause on one part, the security is meant for user access, you are speaking of user use to communicate if funds are avaible and for use. Which is fine, what most cards do now right?
In terms of encryption some would maybe be needed as such for transactions, cause transactions are going to be based on a price and a value in which to be able to spend from, which on either side should only be known as such for what side. In the middle is where you speak of and not much a say reasoning for it as being said for use, unless you get you pin code card for use, which adds in security to right of user access of card. Of such then doing additional crypting would be to ensure validating of account to bank for use of credit or varify credit use or funds use on card.
Points addiontal to card as rewards, might need a verify, but given again, points are rewarded to specific locations, these locations would need to be able to check to see what and where points could go from card. Right? Cause you arent getting ahold of say company to use points, right? Accept to verify and balance, Right?