Vidmaster Challenge: Lightswitch

"Let’s dive into this a little deeper and try and address some of the questions that will no doubt arise from the community. First off are the “Vidmaster Challenge” achievements. These three will not earn you any gamer points but there will (eventually) be a pay-off. We’re not going to spoil the fun just yet but suffice it to say that gamerscore isn’t everything. There is a pot of gold at the end of the Vidmaster rainbow and it is something you will want. More details later."

- SketchFactor

Vidmaster Challenge: Lightswitch is an achievement added in TU2, in which you must achieve the rank of Lieutenant in any playlist in the TU2 EXP progression system.

It has been announced that while the Vidmaster achievements do not give you any points, they are worthwhile for some mysterious prize when you get all of them. The preceding statement at Bungie.net confirms this.