Still, getting it right in-camera with a JPEG means I have no pp
work at all to do, even if its only batch processing. And if I'm in
a studio environment, or even on location with enough time to
optimize my lighting, there's no reason I shouldn't nail WB and
exposure to produce an ideal JPEG.
It isn't just about "nailing" the settings. Sometimes, you set the
camera up to capture exactly what you thought you wanted at the
time of shooting-- ie. "nailing" it-- but later decide that you
want all the images to have a little less contrast, or a little
more saturation, or a slightly different tone curve, etc. It's the
equivalent of changing your film emulsion AFTER you've taken the
shot. Different film emulsions deliver different renderings of the
same scene. With RAW, changing the "recipe" settings essentially
allows you to change the rendering of the entire shoot, or a
segment of the shoot, just as if you had used a different film.
Basically, what RAW allows you to do is not paint yourself into a
corner-- ie. being "nailed" to a certain set of image settings.
Sometimes, it can just me a very minor tweak to WB that you thought
was "nailed" at the time of shooting, but upon later review you
decide that you want it tweaked just a bit.