Having made the mistake of writing a couple of them, I’m pretty sure the only uses of non-fiction documents longer than ~30 pages is

* As a reference; people can look look up just the algorithm they want

* As a token that says “I’ve thought about this problem”

(The former is somewhat a subset of the latter. All of the stuff they didn’t read when they used the work as reference was there to provide them confidence that the algorithm they plucked out of the thing had some thought behind it).

totally. ive made some 10 pagers documenting topics ive THOROUGHLY considered and had my work peers review. same as you, the purpose is to point at it 5 years from now and say "the answers in there"

but when my coworker pays to create documents on topics he hasnt considered, for ideas of projects which dont exist, it feels like an exercise in text generation and i become mildy put off for the onus of reading it. i know it was written without purpose and while there are possibly novel tech and ideas in there, it feels like being handed less than a rough draft because it lacks any aim and intention

now, i expect he would get much more from it. hes the first party audience who reads the doc and sees a valuable project somewhere inside of it