Foils are easier to work with then metallic paints. In West Palm about 3 years ago I did a cupala 28' high above a grand bathtub and spent 3 days getting that room the gold in the can.
Now you do need to basecoat as that ceiling is black and then you apply size and then foil, then you need to glaze it but the main difference between metallic paint and foil is the color richness and the true look of what you are after. You can apply as many as 5 coats and never get the colors that come out of foil.
The pics below are all foil finishes with the exception of the desk before as I just wanted to show you how beat up it was prior to starting. The 1st pic is holographic foil which has been glazed over, the 2nd pic is gold foil on the base of the desk, the 3rd is the desk before, the 4th is a gold foil over a raised wallpaper which was painted espresso, the 5th and the 6th is a gold/copper foil over skim coated drywall with raised stenciling and has 14" faux'd crown molding to look like old distressed wood.