Re: Why paint instead of gelcoat?
If you think the amount of work required to get a quality paint finish is massive, you don't want to know how much work a complete gelcoat recoating job would be.
When gel is sprayed into a mold as the first layer of the lay-up, the exterior surface is pretty close to being ready to polish. Unfortunately, that's a one-time deal. Any additional gel that's applied after production will need to be applied (spray preferred) then wet sanded and finally compounded and polished. Add in the time required to remove and/or mask hardware and deck fittings, fix minor nicks and gouges, prep sand, etc, etc, and you're talking about a major job as well.
Paint is a lot more forgiving than gelcoat, and if properly applied will dry to a shine (i.e., you've crossed the finish line.)
With gelcoat, once you've applied the gel you've still got the second half -- or maybe even 2/3 -- of the race to run...