The JSON Pointer is a standard defined by the Internet Engineering Task Force (IETF) under Request for Comments (RFC) 6901. The standard basically says that a JSON Pointer is a string that identifies a specific value in a JSON document.
Without a JSON Pointer, you would need to parse the whole message and iterate through it until you find the desired value; probably lots of ifs, elses, and things like that.
So, JSON Pointer helps you to decrease the written code dramatically by doing this kind of operation in a very elegant way.
