I think the non-KYC exchanges may use stablecoins as collateral due to the inability to service fiat. But Kraken for instance has BTC-USD perpetual futures [1]

I think the non-KYC exchanges may use stablecoins as collateral due to the inability to service fiat. But Kraken for instance has BTC-USD perpetual futures [1]. Presumably a large mortgage lender would write their own contracts or collaborate with an exchange for a product using their own mortgage contracts instead of USD on margin as collateral for the loan. [1].https://futures.kraken.com/trade/futures/PI_XBTUSD https://futures.kraken.com/trade/futures/PI_XBTUSD