From what I understand Skippers are upgrading cadets to command positions. They can do this because a majority of their flights are charter not RPT and therefore don't require an ATPL or 500 ME command. This does however limit those pilots to the charter flights only though.
I know for a fact that the Jetflite cadet programme used to provide cadets to Skippers and I think it it was either 2006 or 2007 they stopped. I assume this was to take on the fast track cadets intead?
YPJT, a cadetship is certainly one of the quickest ways to get on a turbo prop and I would imagine that most of them would be basing their training on multi-crew turbo prop flying. I certainly wouldn't think it would be a bad way to get in.