[lowkey]

Unless the stablecoins are preferred over traditional fiat USD for some use cases.

For example with stablecoin cryptocurrencies I can move an arbitrary amount to another party with no risk of censorship, no permission required, on an arbitrary Saturday morning at 3am if I wish - all in about 10 minutes. This is impossible with USD fiat.

Because of this utility, there is significant demand for stablecoins by traders and institutional investors who prefer stables over fiat and are willing to pay a premium for this utility.

Also my 50x claim on interest paid on savings is based on a typical US bank paying 0.1% APY.

50x 0.1% = 5% which is lower than many stablecoin savings products offer today.

What makes you so certain that a 5% APY on stablecoins is unsustainable at scale or a scam?

[oblio]

Because you need overhead for classical banks to be huge for long term interests for deposits to be that far divorced from inflation.

Their overhead is big, but not that big, plus they follow the central bank interest rates.

Your case is a localized anomaly, this can happen with regular banking, too, but it's not scalable. You can't ramp that up to population levels.