Is this available also if you hold in your own wallet? Germany has something similar, but it turned out to need to move your coins in a custodial wallet, which sux.
Also, is this available only for Croatians? (one can always hope

)
However, the 2k EUR/day should be more than enough for everybody, so, yeah, well done Croatia!
You can hold wherever, it's based on the moment of conversion back to FIAT based on the FIFO (First In First Out) method.
So, you buy BTC now, transfer it to any wallet and come 2022, you can transfer the same amount of FIAT you invested back to your credit card without paying a fee. It's the same with stocks.