When it comes to parsing JSON, they are indeed not doing the same thing. Buger's parser is not unmarshalling into an annotated struct.

But often that struct isn't your end goal in life, such as when your data is being transformed, dispatched on, or being moved into another yet data structure. In that case unmarshalling to an intermediate structure, while convenient, is also extra computational work.

Buger's parser isn't the first thing I'd reach for, but if JSON parsing performance is an issue, ObjectEach() can be used in many places where you'd otherwise invoke json.Unmarshal.