It should be obvious end to end encryption and ephemeral messages are for different threat models. And blocking iOS backup but allowing Android backup, desktop

It should be obvious end to end encryption and ephemeral messages are for different threat models. And blocking iOS backup but allowing Android backup, desktop backup, and iOS history transfer is a really bad way to implement ephemeral messages. You assume someone will know what they'll want later when they receive it. Saving several messages together is tedious in most apps. So is organizing saved messages.