It's handy, and consistent with the UI (IMHO) that you can pass a feature class to this function. Layer inputs to tools can take a layer file, layer in the map, or a dataset. I agree it should be documented!
If you find anything in the help you don't like, you're welcome (and invited) to provide feedback using the button at the upper right of the page.
I know these comments gets read and used because when I provide my email address I get a personal email back from the doc team.
I agree that GetLayer may be a better name for the function. If you add it to ideas, I'll vote for it!