CD Stoplight pen vs Sharpie Green Marker

I recently tried Sharpie green permanent marker($1.29) to paint the edges of some CDs my player had trouble reading and had very good results with it.What is the advantage of using $8 pen?
sol322 gave good advice....supposedly the markers help prevent laser light dispersion....if you can hear a difference and like it go for it....tweaking if part of the fun of this hobby.
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finger nail polish. Find a way to spin the cd, then gently touch with brush. Art supply stores have paint markers. These 2 ways are better than sharpie markers. Markers still allow light through.