Yes. When I'm done with JSON-specific operations, I'd like to use traditional libraries to do non-JSON-specific things, and I would like to avoid having explicit conversion to Maps and Lists.
Also, using POJOs can lead to more readable type signatures - it's easier to determine what the method getBooks of the Author POJO that returns List<Book> is about than a Map<String, Object> that has a List<Map<String, Object>> mapped to the key "books".
Bit of an impedance mismatch between a serialisation format from a dynamically typed language and a statically typed language.