The author dismisses WARC, but I don't see why. To me, Gwtar seems more complicated than a WARC, while being less flexible and while also being yet another new format thrown onto the pile.
WARC is mentioned with very specific reason not being good enough: "WARCs/WACZs achieve static and efficient, but not single (because while the WARC is a single file, it relies on a complex software installation like WebRecorder/Replay Webpage to display)."
I don't think you can provide a URL to a WARC that can be clicked to view its content directly in your browser.