I think people downvoted version 1 of my comment, which was less interesting and more cranky. But the downvotes were helpful; they gave me an excuse to make it more friendly and add a relevant story. :-)
I should have guessed that these were just low-res previews: I read too much into the comment that they were real cheatsheets.
Even with high-quality vector text, though, I wouldn't find them useful because of the layout. It's great if you print them, but if you like to have everything onscreen, a scrolling document is easier to read.
AFAICT these are low-res previews of high-quality PDF cheat sheets you can buy.