PHP already has built-in classes and functions to handle date...

PHP already has built-in classes and functions to handle date and time differences, as well as powerful parsing functions. It is difficult to see what this adds to the standard library. Also, the difference-calculating function is just that - a function - and its class wrapper does nothing. Looks like it was written by someone who does not understand what classes are about.

This is my comment on your understanding of the working class. Not every class needs to be a breakthrough, as well as not everyone needs to make a breakthrough in php. It is important for its use in practice.