Turn signal side repeaters are mandatory in Europe. They are mean to be seen at all angles from the side. That's why they bulge, not sit flush with the body.
Put it on thick enough, and the rocks would probably stick to it and add texture. ;-}
I do know PlastiDip never really hardens up and holds up fine on my wheels anyway. I get a little rust showing thru, just touch that up and I'm good. I did these a couple years ago.