And what is the principle of trading precisely on a decentralized exchange? The fact is that at the moment there is not a single truly decentralized exchange on which there is liquidity. I see no problem using centralized. I think in a few years there will be really big and decentralized exchangers.
The government are those who will benefit from the exchange and other fees. Decentralized exchange are good but there are variety of factors to consider for it to become effective. It is not easy for a society to really adapt bitcoin because it is very hard and very hassle to use. Exchanges are the one who make the transactions delayed because it really causes some errors. People only appreciate centralized exchanges because they not yet tried to have a transaction using decentralized exchange for a more secure trading.