Asking because just curious, no problems - true, I don't drive that much under wet conditions. And yes, there might be some protection effect keeping water away from discs when driving in heavy rain wet conditions, as well avoiding getting small gravel pieces damaging the discs and pads. Just don't like the unprotected discs...
On my daily car, the delayed braking in heavy rain was well solved by ATE-Power Discs with a kind of elliptic groove, very effective! So, drilled discs might have similar effect.
P.
