Usually, chrysalis of butterflies camouflages with the surface it is attached to, for protection, as I understand it. There are exceptions, though; For example, the golden chrysalis of Euploea core is reflective and literally pops out of its background. My point is, what is the evolutionary advantage of that?
Edit: user -personjerry pointed out that shiny colours indicate poison. So the main question now is, if the aim was to scare off predators, why aren't they red/black in colour (as red means impending danger in the animal world)? Also, wouldn't developing a red pigment be much easier? In these cases, is the colour predetermined?