Right, my point is that for illustration purposes, putting [0,2,0, 2] for the premultiplied alpha value is a bit easier to absorb than [0,0.007843,0, 0.007843], which is harder to "see" because of all those zeros, etc. Think of those 0-255 values as linearized (which I note in the article) and as shorthand for me writing [0/255,2/255,0/255, 2/255], which is also hard to read.
Yeah, everyone rags on PNG, but I'm happy someone spent time making it happen - no one else was doing so back then. The only other option was TIFF, which was and is "a file format for everyone", with too many options and weirdnesses. PNG has some definitely weak elements, but was better than a cease and desist letter from Unisys or the madness that is TIFF. Hey, PNG's nothing compared to the fact that a large portion of 3D models are still shared using Wavefront OBJ as their format, an ancient format for a non-existent product and with no one at the reigns saying how to interpret the spec (Autodesk owns it, I guess, but there's no OBJ czar here).