It's relative, though. As cash and cards become more impractical by the day, they will eventually be less practical than even crypto.

The work of processing a credit card transaction is 1/100000th the work of a blockchain transaction via proof of work. Credit card transactions can get enormously impractical and it will still be more practical than a purposefully-inefficient distributed database.

Most of the stablecoins are on Ethereum, which is Proof of Stake, and the remaining is on centralized chains like Tron.

Gas fees on Ethereum L2s like Base cost $0.0016 to send USDC, and $0.00064 to send ETH.

Stablecoins don't use proof of work.

how are cards impractical?

It’s very practical if it’s stablecoins

I'm not sure what a stablecoin is beyond what I can intuit from the name, but the fluctuating prices of crypto seems like a detriment. However, couldn't the prices of materials listed on itch just update live to reflect the value of whatever coin they settle on using?

Stablecoins are tokens issued by a centralized issuer that is backed by fiat and /or US treasuries (especially for USD stablecoins). This would mean USDC by Circle, or USDT by Tether, but there are more stablecoins issued by others as well.

Itch could update the prices pegged to BTC or ETH, yes, but they'd either want to keep them, or liquidate them to USD, in which case there is risk of fluctuation between when the token is sent, and when it's liquidated.

So stablecoins are reinventing banks just with less regulation?