It’s a ridiculously consequential bug and they don’t seem motivated to even comment.
Pretty sad.
They don't have the resources to store files on the cloud, even encrypted, and don't appear to have taken WhatsApp's approach of backing up unencrypted media and messages on user's third-party cloud services like Google Drive and iCloud.
You can mitigate this by having disappearing chats (current longest self-destruct time is 4 weeks), or by going to Settings->Data and Storage->Review Storage and deleting the largest files.
This isn't a great UX design, as users are not informed there is a problem, or how to solve it.
When you select “delete all message history” it should free up the disk.
Also, what good is secure encryption if i have to give out my phone number?
Actually how could you possibly deliver secure messaging if it doesn't work with simple identifiers you already have like your phone number? Everything should be secure, that's Signal's thesis.
This reminds me of the people who were convinced HTTPS should only be used for "important" stuff that "needs to be secure" like banking and so it's wrong to have HTTPS on your blog, or news site, or whatever.
It's tying my Signal identity to my phone number. To speak in US terms, you're safe from your comms being intercepted by the KGB, but now you're a person of interest to the CIA :)
Every time I upgrade my phone I have to reformat & disable iCloud lock and hand in my device before I get a new one. So Signal's workaround of having two phones side-by-side to transfer is a non-starter. (Also useless if you happen to physically lose your old phone.)