Co-founder of Tangem here. The crypto value is on the Tangem Notes, inside the secure chip in the form of a unique private key which is impossible to copy. You can redeem any Tangem Note directly to blockchain without a third party using an open NFC protocol.
What I was able to deduce from the linked article in the OP, your note is suitable for users without any technical knowledge regarding Bitcoin and the underlying technology.
You say that the private key is stored in the card itself, and your app will connect to the Bitcoin network to check the balance or use the funds.
What I'm interested in is how you plan to protect the users' private keys (even from employees of your company)? This is important, even though the value stored on these cards is not so big.