Ever try to use log4net or NLog without code examples in their documentation? That is just one example out of thousands for why "most" documentation needs code examples and example usage; especially if you are not used to working with the product, etc.
That depends... You seem to be assuming that "documentation" means "documentation targeted at programmers". I can very well imagine documentation for an accounting system, a video editor or a computer game that does not contain code samples.
You may of course argue that "Clicking this button is the equivalent of calling an API, so for documentation purposes, illustrating the effect of clicking the button is a code sample". OK, I'll accept that, but to me that is twisting it quite a bit.
Exactly! Documentation should focus on the why much more than the how. What assumptions were made? What are the general inputs and outputs? What's the life expectancy of the application? What critical technologies are involved? Stuff like that. If organizations need documentation to explain the code itself (at least at a low level), then code is quite likely badly written.