This seems to be an unfortunate case where a feature has a misleading name.
You already had secure and encrypted backups on your phone, which you could copy and restore, if you remembered to copy them, and write down a very long password.
The new feature is apparently a way for signal to sell cloud services.
I do think cloud based backups are very useful for less technical people. But it does not really matter if your (properly encrypted) signal backup lives on a google drive/apple cloud, or on a cloud service managed by Signal.
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