The chip is highly secure and independently certified. Our proprietary firmware is beautifully simple and audited by Kudelski Group, look it up.
https://twitter.com/kudelski/status/994105585825144832The chip and firmware guarantee no import or export of keys is possible the chip creates it's own unique private key and can never disclose it. There's manufacturer attestation mechanism on the same secure chip to prevent any chance of counterfeits. You don't have to trust anyone.
You're contradicting yourself perfectly. It doesn't matter how simple the firmware is, it's proprietary, and that means users cannot verify your claims without spending the BTC from these notes.
Tangem notes don't need "independent certification" or "manufacturer attestation" if there's no need to trust anyone. That literally means customers are being invited to trust your attestations and certifications.
A significant part of what makes Bitcoin valuable is that anyone can verify the validity of a payment, not just a company paid by a manufacturer to do so. The previous physical Bitcoin producers (or at least Casascius anyway) were very upfront that trust was essential to their product, that made it easier to trust them. The fact that you at Tangem either don't understand that, or are wilfully misrepresenting the fact, makes it much much more difficult to trust you or your notes.