I use it all the time, preferring it to everything else¹. Especially when reading the Python documentation.

1. <https://news.ycombinator.com/item?id=44213303>

I use it in particular for bash, mostly because it has better expositions for parameter expansions. To the point that I know searching for "%%" in particular will get me to the correct section.

For everything else… I think it's also necessary for GNU find expressions?

I occasionally use gnu info. My favorite tool is pinfo which has a man mode that adds navigable links to cross references in man pages and can shell out to hyperlinks. I usually have that aliased as man.

I use the online versions, e.g. https://www.gnu.org/software/make/manual/html_node/index.htm.... In this form they are pretty good documentation (although that is usually due to being comprehensive and adequately written, nothing really to do with info beyond supporting adequate structure).

No. Every man page is better, concise, easy to access.

GNU Info should be like a browser but it makes something simple into something complicated.

No. I have no idea how it works, it's like being a new user in vi and not knowing how to quit.