Re: WHY CSL's
This is the way that I see the difference between CV and CSL:
CV - the natural ability that most people possess and can use at all times and conditions (unless the GM states otherwise).
CSL - the refined training that the individual has received through years of practice (either through actual combat or danger room combat)
As a result, any beginner will be able to use upto his full CV, but only after years of training will the levels of CSLs appear that are normally seen on the character sheet.