n=1 and all. I think "almost never used" isn't far off the mark. All of this sounds like hardcore nerd territory to me, with the possible exception of Signal, which still has strong nerdy vibes and is very tiny compared to its competitors. Sending encrypted e-mail from Linux definitely seems to be something that's almost never done, at population scale. If that isn't crypto nerd territory, what is?

If you were looking for everyday things lots of people do that make use of powerful security technology, Whatsapp's e2e encryption or https would be much better examples I guess; people actually use these en masse and can do so all by themselves, without support or nagging by experienced hardcore nerds.