As mentioned in parent comment:

> Signal does not care about users and prevents backups on iOS. Lose your device or delete the app due to some issues and reinstall? All your chats are gone!

Switching out devices is something that happens often enough for many users that transferring history should not be an ordeal. Even the most careful users will occasionally break their phones, and sometimes people need to switch platforms for whatever reason.

WhatsApp suffers from this issue too, at least when trying to migrate histories between platforms.