What is the difference between REST API and Apex REST API?

Could you please explain to me the distinction between a standard REST API and the Apex REST API? I'm particularly curious about how they differ in terms of functionality, usage scenarios, and any specific advantages or limitations that Apex REST API might offer over a conventional REST API. Additionally, I'd appreciate it if you could elaborate on the use cases where Apex REST API might be more suitable than a standard REST API, and vice versa.