The more popular the DeFi exchanges the more people use them. So the liquidity of DeFi exchanges grows and they are albe to win competition with centralize exchanges.
People must be sure that their funds are kept in a safe place. The accounts on centralize exchanges can be blocked or banned. That is why many people prefer to use DeFi products and their adoption grows.
Yes, we could see the volume on here.
https://www.theblockcrypto.com/data/decentralized-finance/dex-non-custodialSo the trend did really make out some effects in terms of volume
but lets just accept the fact that it couldnt still beat up CEX when it comes to that.
Why? As long it doesnt really involved fiat conversions then it would really be staying below CEX.