I agree with what you're saying and no I didn't confuse anyone with saying at 500hrs put him as a captain.

However, there are times when an FO has to stepup and go to bat. What if the captain is making a bad decision? Will a young 500hr FO who doesn't really know any better stand up to him? Being young, with low time, and second guessing a captain could put you right on the crap list.

What happens if the capt all the suddent slouches over the controls because of a heart attack like the one that happened a few weeks ago? Things like this might be rare but that is exactly why an FO is needed.

The cockpit of a commuter with pax onboard isn't the place to teach. It's a place to operate. The captain already has plenty on his hands and needs the help of another. Not have to spend was little time he has to teach. Now if the aircrafts empty and he wants to brush up on a few things then have at it. But with pax in there they are both there to work.