There are big wishes for Signal to adopt the perfectly working Flatpak.
This will make Signal show up in the verified subsection of Flathub, it will improve trust, allow a central place for bug reports and support and ease maintenance.
Flatpak works on pretty much all Distros, including the ones covered by their current “Linux = Ubuntu” .deb repo.
To make a good decision, we need to have some statistics about who uses which package.
SMS is also the common standard for talking to people.
For the vast, vast majority of people, the technical security of, ‘hey, you want to catch a movie next saturday’, is far less important then the message actually getting through.
Qute simply, it is far more important for a communication method to be easy and universal then to be secure against attacks the vast majority of people do not think they will ever encounter. When most people want to tell their neighbor two houses down that the dog has gotten out again being able use the app they already use to communicate is far more important to them then then a bunch of technical jargon about end to end encryption.
Why is email less bad than SMS? It’s about as (in)secure.
Email also fulfills a different role, as it is for longer, more formal, and less time sensitive messages. Nevertheless, more modern and technical encrypted email clients go out of their way to still work with unencrypted messages insteand of being deliberately incompatible as Signal is.
Email uses modern TLS, SMS uses some ancient encryption from the 90s or so, that just doesnt work.
If you trust the servers email is fine.
You can use Deltachat to chat over email. The protocol is universal its just how you use it.
Trust me a signal/xmpp/matrix message could look like an email too.
Email + Encryption is poorly optional yes. But you are asking for an internet chat service to support a different, ancient, insecure and unprivate protocol that has nothing to do with it.
Deku SMS supports encrypted and unencrypted SMS, this makes sense.