nuts through the hubcap, or remove the little screw-on plastic caps to access the wheel nuts. So there could be a purpose.
Case and point: 1990-1994 Chevrolet Cavaliers (plastic caps & the wheel nuts secure the hubcap) 2008+ Nissan Rogues (access the wheel nuts through the hubcap so you don't have to pull the hubcap off if you are doing a wheel swap).