Less maintenance : Since the node in a Dex cryptocurrency exchange script is not run in the server, this is considered more secure. This also allows you to spend more time and money in maintaining the security of the exchange. On the other hand, you will have less control over the tokens and assets in a Dex exchange.
2. Less choice : If you plan on running an exchange using a dex Crypto exchange software, you have very less options. Most probably you will have only a selected few crypto assets you can support. Unless you run a cross chain atomic swap enabled exchange, you will have very less options. On the other hand a P2P exchange enables you to have as many coins and tokens you want listed.
3. No variety : The earning potential is limitless in a centralised P2P exchange. On the other hand, a dex Cryptocurrency trading script only offers smart contract based mining or gas fee earning.
4. Less cost : An exchange setup using a centralised bitcoin exchange script needs more infrastructure. Which means you need to spend more on servers as you grow. But a decentralised exchange runs smooth on even a small shared server, as a bulk of the resources required for execution is decentralized.