Earlier quoted context omitted.
This "sideloading" thing is mostly to enforce US sanctions against countries like China, Russia and Iran. So yes, hundreds of millions of people care about this.
I don't think it follows that the entire population of each of those countries automatically cares about this just because it's, ostensibly, being done to enforce sanctions against them.
Normies in sanctioned countries install banking apps by "sideloading" APK's downloaded from an official site. They all know exactly what "sideloading" is and why Google is banning it.