[snazz]

Then if you need those features on a regular basis, you have to make a lot more clicks to access that hidden menu. I personally really like the Microsoft menu paradigm where I can either click on the File, Edit, ... menus or press Alt and then a memorized sequence of characters. It allows for discoverability as well as efficiency.

The Emacs equivalent also works nice: press a memorized key binding for something that you do frequently, or press M-x to type into an autocompleted (and fuzzy searched, with the right packages) list of commands for some particular functionality.

[angleofrepose]

Or, better yet, a UI builder accessible through that "advanced features" menu that lets the user decide what is accessible and easy.

[TeMPOraL]

Or, in case of Emacs: just bind the M-x feature you're using to a key.

The overall principle is sound, IMO: present the "simpler" UI up-front to not overwhelm newcomers, but have advanced features available and a means to bring them up to front of the UI, for repeat users.

[snazz]

Like Firefox! I agree, that’s a very nice feature.

[Noumenon72]

I also love that I can put things in Word's Quick Access toolbar and then Alt+1 will do the first thing, etc.