I can see why backups might be needed for a dozen years, and I can see why encrypted backups might be needed, but outside plainly fake requirements like those of "national security" why would encrypted backups be needed for a dozen years? Aren't we throwing everything sensitive away after seven years? After that isn't it mostly about preserving history? Even things like balance sheets that might be sensitive today will be too out-of-date to be sensitive a dozen years from now.
The obvious counter-example is my library, however old my photos or music or videos are I'd like to keep them for as long as possible, and because they're private I'd like to keep them in an encrypted form