I think the recovery image files might still be updated in the future, so that people don't have to install a bazillion of updates if they ever do a factory reset.

This is a huge benefit of this recovery implementation (easy to update files on a separate partitions) compared to the old one (basically unupdatable/hard to update BTRFS snapshots).

Still even if they for example kept the last two recovery file versions around it's unlikely it would every use the full 7 GB available.