Coach Lighting The Easy Way...

Well it means you don't have to cut the chassis/bodywork either which means they can be converted back if you want to sell them on.  Also look at the other opportunities, while you have it apart you could add some glazing to the windows for PlaRail carriages that don't have it (most in my experience), maybe even add some interior detail or some people or whatever.  The world is your oyster and think how impressive it would look on your youtube channel if you did have lit carriages that others can't buy lol!