The Czech Republic finally gets it too...
I was quite looking forward to 19 February — I was curious how it would work. I didn't hang around and waited in the morning to see what would happen. By some magic the option appeared in Wallet to add a payment card. I pointed it at my Mastercard and waited — unfortunately Česká spořitelna only supported VISA cards at that moment. So again: point it, wait for the card number to be recognised, confirm validity, enter the CVC, and done.
Technically, Apple exchanges card information with the bank. Most likely it's a hash of all these details. As a result, the merchant doesn't know your card number or expiry date — they only know it's a valid combination. Which is definitely a step forward for data security. What strikes me as slightly controversial is the absence of PIN confirmation for payments over 500 CZK. However, to make a payment you need active Face ID/Touch ID, which I take as that additional verification.
When will Mastercard holders get it? According to the bank, during March 2019. Nothing to do but wait.