Not really a silly question; the logic is that it helps bridge the gap between flying a Duchess / Seneca and a high performance turboprop. The Q400 will climb at 3,000fpm without breaking sweat - at low levels it's pretty much like a jet, only more of a handful. The JOC is also a tailored to Flybe calls and SOPs, which provides a good head start for the type rating course.
From memory it was introduced in late 2007 or very early 2008, which is why Deano was spared it.