What is the difference between a crypto exchange and a trading platform?

Could you elaborate on the distinction between a cryptocurrency exchange and a trading platform? I'm particularly interested in understanding the core functionalities and how they differ in terms of user experience, available cryptocurrencies, transaction speed, and security measures. Is there a general rule of thumb to determine which is more suitable for a particular trader's needs? Additionally, are there any specific features or advantages that one might offer over the other? Your insights would be greatly appreciated.