If Signal was not simple, my family and friends would likely use Telegram or WhatsApp. Even switching to Signal required a number of (general) newspaper articles criticising the status quo. It's likely not optimal, but okayish and sharing opinions and holiday impressions feels a bit better.
Switching a service is a slow, difficult process and many contacts will not follow, given they would abandon other contacts among friends, family, parents at school, sports teams, ... (now, I'm here, using 4+ solutions).
If training or even curiosity for the technical process is required, very few people will follow. If it takes me (with strong IT background) more than 30 minutes to understand/implement, I may have a decent private solution, but I will feel quite lonely soon.