Ryan paid his and Gwen's bill while Naomi paid for her own. The reason Ryan had to pay for Gwen's bill was… because she insisted.
Although as soon Ryan paid for Gwen, Gwen pulled out a hundred-dollar bill and handed it to Ryan. Ryan was totally confused about what was going.
Ryan had to exchange the money and transfer it back to his crypto holdings. This world had developed a lot and… decentralized finance had taken over the world.
Dollars were still a currency mainly used in this world but cryptos were the main thing the transactions were done. For paying the taxes, the government did not accept any cryptos.
The amount displayed in the bank accounts of people is nothing but the holdings of a single person's cryptos. Every bank transaction was done in cryptos but the amount was shown in dollars by the Bank of America. Because the bank was America's, the currency was also USD. It does not matter what country you are in.