I agree that Signal is nice, but I think the point here is that Delta Chat is decentralized
Imo it’s already difficult enough to convince friends and family to use Signal. Delta Chat would be even more difficult to pull off.
How is it different? In my experience it’s easier as they’ve already heard of email.
The difference is signal has millions of users and most people have already maybe heard of it.
So is Matrix and it’s way more popular. But recommending anything other than Signal at this point is a waste. Fediverse chat is a more complex conversion for many who are still in the connect via phone number stage for chat. Fediverse is an easier story for other platforms.