> Google's styleguide on that subject is also very clear that you should indeed not close void tags.

Only because it results in smaller files. For example it also recommends omitting optional tags for the same reason. I'm really skeptical that omitting these things helps readability (if that's what the guide is referring to when it says "scannability"). If size is at such a premium why not simply preprocess and minify HTML? Recently I tried briefly omitting "/>" from <br> and friends and I wasn't impressed as far as legibility goes. Maybe I just didn't try hard enough... :)