Came here to ask this myself. I get that you can do anything you want to but I'm super curious about the author's motivations. Seriously, why?
Probably for the same reason I have a tendency to make earley parsers for random languages in python and C++ every now and again, something to do that's semi-productive.
If I ever get around to playing with golang you can bet there's gonna be yet another earley parser implementation for whatever grammar I'm currently looking at.