Can use? Yes, some can. Need? No, plus, 10yo+ games freak out with too many cores, such as Prototype 2

A lot of games have fully multithreaded components (for physics or navigation for example). So they can use any amount of cores. Its pretty rare to see a game max out all cores on such a system since they are usually limited by something else first.

Maybe Fortnite cause of the Unreal 5 update?