If you have never heared of satscard or opendime plz take a first look here... https://satscard.com/ https://opendime.com/

Opendime was the first step. But opendime is quiet expansive and got only one slot. So if you sweap the funds of the opendime you can not use it again. The price is 20$. Satscard now got 10 slots and the price goes as low as 7$ so one slot is only 0,70$!

Now here are some new thoughts! With taproot it will be possible to create a transaction which sends the funds away from the satscard to a known address! (maybe a card issuer) So this would solve a problem which is that the card could be destroyed!

Also if you have a good enough synced blockchain you can also verify the founds on the card! Lets say you only need to sync the blockchain once a month. The issued card just needs to have a balance which is some month old! If the taproot fallback is set to 5 or 10 years the funds are save even if card breaks.

I dont know if it would be possible to program this but the best way to verify if a card got a working private key even without internet would be to sign a random message you send to the card. But i dont know if this would break the seal? I think this is the real problem which someone has to solve. How you know its sealed and not just a "copied" card and someone gives you the card and after that just moves the funds. and this all in an offline enviroment?

Maybe you got some thoughts too!