Powell didn't say anything about Bitcoin or Monero, and I don't think you can extrapolate from his statement any implied support for such coins.
Powell wasn't talking about decentralized, p2p crypto.  He was talking about China's proposed issuance of a state-controlled virtual currency.  Powell thinks a transparent blockchain is in keeping with the way China does things, where the government is up everyone's ass and wants to control your very thoughts.  He doesn't think the U.S. is like that.  But the implication is not that Powell supports a decentralized, censorship-resistant coin like Monero.  I think he probably supports a ledger controlled by a central actor like the Fed or the US government, a ledger with some degree of privacy and fungibility.  But the privacy and fungibility you would get with a FedCoin is probably no better than the privacy and fungibility you have in your bank account today.