In the US at least prisoners do not really have a choice of reading material. Men in prison get jacked and read what they can get their hands on which is not necessarily what they might want to read. This is a good DB. Prisoners might also have to pay to read if it’s digital. I would personally contend that it’s harder to read in jail than prison but I don’t have a good study for that. More people go through jail than prison so the ability to read is much lower overall.

The rest of the world might treat prisoners a little more like human beings so I don’t know if this works outside of the US.