You actually believe that every person in the world who shares their screen is aware of computer security best practices? Or are we only limiting this generalization to every one of the millions of YouTube/Twitch livestreamers?

> I can just amplify their stream to hear their keypresses.

Maybe if they have Cherry MX Blues? A normal keyboard would not get picked up by modern apps' recording noise suppression (the filters are designed to eliminate the sound rather than merely lower volume).