If you want to exchange, that is buy or sell, you'll need such a "centralized" exchange. Same for trading.
So even those that keep their assets offline on an airgapped machine in a nuclear bunker, will occasionally move crypto assets on- and off these exchanges. And especially when you hold the crypto truly offline, it's a hassle to get it on- and off exchanges. So you'll probably keep several months worth of sales or buys before moving it.
Point being: even those that still believe in the "decentralized" currencies will have some of their assets on "centralized wallets", even if only for a short time.
And yes, I am aware that one can "decentralized" buy and sell for and to fiat. And yes, I am even aware that sometimes in some situations, one can even avoid exchanging to/from fiat to pay rent or gas. But that's far from practical and probably never attainable.
So even those that keep their assets offline on an airgapped machine in a nuclear bunker, will occasionally move crypto assets on- and off these exchanges. And especially when you hold the crypto truly offline, it's a hassle to get it on- and off exchanges. So you'll probably keep several months worth of sales or buys before moving it.
Point being: even those that still believe in the "decentralized" currencies will have some of their assets on "centralized wallets", even if only for a short time.
And yes, I am aware that one can "decentralized" buy and sell for and to fiat. And yes, I am even aware that sometimes in some situations, one can even avoid exchanging to/from fiat to pay rent or gas. But that's far from practical and probably never attainable.