The fact that `C-h b` is not mentioned in the tutorial doesn't imply that one can't find it or doesn't know how to use it.
There are hundreds emacs commands. The fact that description for any command can be found through help doesn't mean that you've discovered them all after spending 30 minutes reading the Emacs Tutorial.
The point is that the direct link to 'C-h b' is mentioned in the tutorial. That section of the tutorial also has sections on a few of the options in C-h.
That is how pivo found it. By going "oh, I wonder what else is there" and hitting C-h ?
If you're not the type of person that does stuff like that, emacs probably isn't the editor for you. Hell, software development probably isn't for you.
Yeah, emacs is large - and has lots of features. Once you've been through the tut, and spent a few days with the editor, they're quite discoverable. It does make the assumption that you want to discover though.
There are hundreds emacs commands. The fact that description for any command can be found through help doesn't mean that you've discovered them all after spending 30 minutes reading the Emacs Tutorial.