Rocker panels are structural.
One of the first things a manufacturer does, when changing a car from a " solid roof " vehicle to a convertible, is add material in the rocker panel & a-pillar section.
I remember some years ago a Chrysler LeBaron came into the shop to have a tire changed.
When the technician raised the car at the left rear corner, the windshield cracked.
Happened to a few other people as well.
Guess Chrysler just chopped the roof on that one, without re-engineering it properly.