Of course I'm very judgemental towards people who ignore the established knowledge of the field and instead rely on social hearsay. Call me old and grumpy.
Furthermore, reading about functionality feels like a waste of time
yeah, but simplified, this is how you end up with programmers that write an if statement 10 times because they don't know what a for loop is. The waste of time still happens elsewhere.The vim manual only explains the flags and how/where to access the documentation and tutorial. You don't read it to "become fluent" in using the TUI application, you read it to learn about how to run the program from the commandline.
BTW on Linux, I have "man-all" aliased to "man -a", as I want to read all available man pages (e.g. POSIX, GNU, Linux).