I think most (probably all) the open loop gift cards are issued by banks and credit card companies who have money transmitter licenses and are so regulated that there isn't much additional burden for them.

I like the analogy when it is with closed loop cards. One way to put it is that you buy the ecash from the mint and then you spend the ecash at the mint to buy different btc. Kind of like using an azteco voucher with fiat.

Another way would be you buy the ecash from the mint and then you spend it at a shop in your community that also accepts ecash, but under the hood, isn't the first ecash token being returned to the mint and changed into a new token? I thought this is how they avoided double spending. If so, you can never actually spend your ecash anywhere but at the mint. Just like you can't spend a closed loop gift card anywhere but at the store that issued it.

The hard part is defining what service you are prepaying for when you enter the mint with your btc.