> What's the point of a decentralized exchange if the frontend code can be shutdown at will?
You can have decentralization with respect to some components of the exchange and not others. In the case of Paradex it seems the point of decentralization is that you don't have to trust the exchange for custody. That's quite good by itself, even if they can shut down the frontend at will.
Your funds are safe! You can trade directly from your hardware wallet. Your money is never on the exchange. If a decentralized exchange shutdowns you can simply use another.
You can have decentralization with respect to some components of the exchange and not others. In the case of Paradex it seems the point of decentralization is that you don't have to trust the exchange for custody. That's quite good by itself, even if they can shut down the frontend at will.