I prefer info to manual pages and even readthedocs websites by a large margin. Emacs' info reader is great, it keeps track of your visited info nodes as a tree, generates custom indexes for you and allows you to navigate by visit history, node name, index entry and more.

The only downside is that you can't embed images in info, so you end up lots of ASCII art flowcharts ava box drawings. But that's true of man pages as well.

GNU project does not write manual pages, they use info. Most of these manual pages have been written for Debian because in Debian the rules say there should be no program without a man page. But typically these man pages are just summaries of available options without much explanation of concepts.

Personally I have no problem to navigate info because I learned that before HTML was invented. Of course today many people don't accept the idea that one would need to learn such tool. Well, luckily they can read the same content on the Web in various layouts. Working offline is not a very common requirement.