Paint will never hold up as well as powder on exterior parts where the oils from your skin are constantly touching it. There are also more color choices unless you want to custom mix your color for painting. There are textures and sparkles. Matte and glossy and somewhere in between. Powder is a better choice.

Paint is available in limitless colors and can be flattened to any gloss level. Eventually you might see wear through the clear where your hands touch but I dont think it would pose a concern. My concern would be where the lockdown bar sits on the rails. The paint will not hold up to metal rubbing on it so you would need to find a way to prevent that. Powder is more durable in that regard.