After the updates to the article, the takeaway seems to be "you can use AVX-512 dot product instructions to sum an array of bytes to int and get a 15% speedup over more straightforward vector code". That's an interesting point, but it's now well-hidden among irrelevant things like the compressed representation that was only relevant to the article's original point.

It might make sense to resubmit a completely rewritten and pared-down version of the article. The dot product trick is neat.