There are two layers of value on chains that are not bitcoin. There is the native currency and then various forms of tokens that can be transacted. Tokens are things like NFT's or Stablecoins. In order to trade tokens you need to pay gas in the native currency of the chain. For example, ETH on the Ethereum network.

Large financial institutions are already doing work using stablecoins. In order to turn stablecoins back into fiat, you have to take them back to the issuer for exchange. Countries with unstable currencies can hold USD by purchasing stablecoins. And financial institutions can do settlement between each other using stablecoins.