This seems unnecessary if the functional / lambda approach is fully adopted as the data can be understood by looking at the functions that operate on the data,

This seems unnecessary if the functional / lambda approach is fully adopted as the data can be understood by looking at the functions that operate on the data, so there would be less of a need for simplifying access to the data values when passing them into functions. As I have developed more data-intensive computational methods in Java I no longer implement data encapsulating classes but rather just use collections containing the basic data types.