It is a cool concept except for the part where your trust a 3rd party with your private key. I would if a guy could acid etch stainless steel at home and achieve a similar result?
https://materialbitcoin.com/en/
It's funny because when, 8 or 9 years ago I saw them using cards with private keys in paralelni polis, I laughed at it.
Seriously though, wtf is wrong with people?
Discussion
In this case you are not trusting a 3rd party with your private key; they are trusting their private key with you.