Most people's whole family is already using WhatsApp to communicate amongst themselves, especially outside the US. It's not that signal is any harder to use, it

Most people's whole family is already using WhatsApp to communicate amongst themselves, especially outside the US. It's not that signal is any harder to use, it's that you now need everyone to unlearn their "Use WhatsApp" behavior, and the only justifications you can give them is "Facebook/Privacy!". This might work with younger groups who really care about that stuff, but as you move up the age groups you'll start to find people who think "Well I already use Facebook daily, how is this different? Why should I care?", and eventually hit the age group that doesn't know the difference between SMS and WhatsApp, they're all just "messages". Obviously I'm over-generalizing a bit here, but even if I got my parents using Signal, they'd still use WhatsApp to talk to their friends. My parents' parents are even more locked in. Short of charging a monthly fee, I don't think there's anything WhatsApp could do that will get a majority of folks to actually uninstall it.