Both Valve and Epic are private companies and thus have a bit more of a say over what they do than public companies would. Sweeney actually just answers to himself, and I mean that pejoratively, otherwise he would have invested in EGS more to compete with Steam and focused more on Unreal Engine’s near-monopoly in the AAA space.
Instead, he focused on “owning” the metaverse, and courting crypto. If I were a shareholder, I would say he wasn’t acting in my best interests.
Generally, no. If a person has access to your home folder, it doesn’t matter if site-data is site-data or some UUID, the person can still look around and find that data. How to do so would be on the internet, in the source code for Firefox.
Firefox simplifies its engineering efforts and makes site-data clearly visible to the proper user by relying on the system’s security measures instead of inventing its own bespoke ones.