To me the most important and awesome consequence of this discovery is that it means that it has changed how we will search for extraterrestrial life in future. It used to be that when it was thought that it took oxygen, carbon, nitrogen, hydrogen, sulfur and phosphorous to make life, and that that was the only way to make life, that was what was being searched for on other planets. Now arsenic is in the mix, and because it seems the reason phosphorous was so easily replaced by arsenic is because of their similar atomic weights, it becomes plausible that there are many other elements that'd do the job as well. I really don't think it's hyperbole to call this a game changer, it's basically throwing the doors wide open with regards to what constitutes life and how this affects the odds that there really is something else out there.