Centralized crypto currency exchanges are not so bad when it comes to converting your crypto funds but it is not the best when it comes to safety and the flexibility of being autonomous when exchanging. Moreover, incidences such as the infamous Mt. Gox hack and Bitfinex hack are not a news anymore given that it went viral and a lot of us already know about it.
Decentralized exchanges in particular have a lot of potential to help the market thrive. They ease the process of trading, eliminate several security concerns, and make exchange between any and all coins a possibility.
The latter is, in fact, its greatest advantage. With an exchange running on distributed ledger technology, I could trade with you for any coins you hold without ever having to pass through the liability of a third-party exchange. You could hand me a dollar for my 61 rupees immediately, and, in the case of cryptocurrencies, the exchanged tokens could be traded and used anywhere, rendering government regulation almost entirely powerless to put a stop to it.
It is this peer-to-peer nature that makes decentralized exchanges so valuable. Centralized exchanges, as the name suggests, involve a supposedly trusted central entity that performs the operations on behalf of its customers. The trouble with this is that this entity is an ideal target for malicious attacks. It holds the credentials and funds of all its users, which makes it vulnerable. If this entity is breached, the funds of so many are lost.
However, in a decentralized exchange, this weak point does not exist, as the exchange mechanism is not based in any particular location, entity or server. It is a widespread network where, if one or two parties are compromised, the others remain unaffected. Server downtimes also no longer become an issue. The lack of an owner, i.e. single point of control, makes it resistant to government censorship and taxation as well.
Source : https://www.investinblockchain.com/best-decentralized-exchanges/
Source : https://journeyto100k.org