SimpleX has some interesting ideas, but also some shortcomings for people who want a practical messaging service. For example:

• It is funded by venture capital, which calls into question its longevity, and even if it does manage to stick around, suggests that it will be leveraged to exploit people once the user base is large enough.
• Its queue servers delete messages if they are not delivered within a certain time frame (21 days by default). Good luck if you take a vacation off-grid for a few weeks.
• No multi-device support. (This means a single account accessed concurrently from multiple independent devices.) The closest it comes is locally tethering a mobile device to a computer.
• Establishing new contacts requires sharing a large link or QR code, which is not always convenient.
• No support for group calls.

I would not recommend it for talking to family members and people in general, which is what OP requested.