Another article I read recently stated that it's simply much easier to use SciHub to search a vast trove of papers than it is using the individual tools/websites of those holding these research papers hostage behind their subscriptions.
Author of the post here: I know no researcher in the life sciences who's using the university search systems. Instead people are mostly using Pubmed or Google Scholar.
But that doesn't solve the access: Finding the PDF you want on the publishers website can be a huge pain. So people just paste the DOI/Pubmed-ID etc. into Sci-Hub to get right to the PDF.
You are just one person.. I don't have to do anything to access articles other than instantly visit the article page and download the PDF in one or two clicks.
I still think that data represents simply which countries found out first about sci-hub. There was a science article showing that it's used nearly everywhere now, because it's actually easier to use
I guess up to a point that's also the case, but it's harder to quantify when they found out about it. And sure, it's used basically world-wide by now, but there are still inter-country differences that aren't only explained by the time people learned about sci-hub :-)