Yeah, I was evaluating a few group chat options to replace iMessage for a large group, and the lack of message backup and strong multi-device support is the reason Signal probably won’t work. One of the most confusing aspects of iMessage (before recent years) was that it didn’t sync chats to all devices. Some devices could get into a messed up state, not have all your messages, etc. Apple solved that problem with iCloud backup, which lets the cloud store messages.
Not seeing your complete chat history on a new device is just not tenable for the average person, and a selling point of signal was that I could use it on windows or Linux, where I can’t use iMessage. I also heard adding signal on an iPad or second phone cousin be messy too.
Compare that with telegram, which is extremely fast across any devices, has even more features, and is slightly easier to use…
I mean, encryption in transit and at rest is good enough for most people. I agree philosophically with e2e encryption, but practically, is it all that important for average chat users, especially if it means sacrificing features people actually use?