A correction, the documentation says of sleep mode: "sleep mode disables all NVDA commands and speech/braille output for the current application."
That "for the current application" proviso is something I just glossed over. I also glossed over "speech/braille output," as that doesn't include other audio output, at least as stated.
Sleep mode seems to be a sort of temporary application profile only for the application that NVDA is running over at the moment you invoke it.
I could have sworn that there was, for lack of a better way of putting it, a "global suspend" command for NVDA where it continues to run, but does absolutely nothing while suspended. But if there is I haven't found it with a quick search.
Brian - Windows 10, 64-Bit, Version 21H1, Build 19043
Nothing in all the world is more dangerous than sincere ignorance and conscientious stupidity.
~Martin Luther King, Jr.