> simple way to get something running where I could easily onboard friends/family

He's not talking about himself, he's talking about (non-IT) friends and family. Most of them probably would be barely able to find the register dialog on HN, that's at least what I would say about my non tech-savy friends. A good chunk of them doesn't even have a PC.

For those people, Signal is optimal. Its onboarding and usage is a lot easier than Matrix.