It sounds like this would prevent users from backing up their own data, which is hard with localStorage and sessionStorage, and instead having to rely on the site owner.

However this doesn't go into any detail, so maybe they have some convenient way of being able to access these files in mind, but we'll never know. It reminds me of another shallow dismissal by Mozilla: https://github.com/mdn/content/pull/36294 https://webreflection.medium.com/mdn-doesnt-trust-you-should...