Metal acrylics are metal paints on a water-thinnable base, which means they can be brushed at the bench with no solvent and no ventilation to arrange. They suit small metal detail such as buckles and fittings, tool heads, blades and the worn edge of an armour plate, where setting up a gun would be out of all proportion to the job. The film is thicker than a lacquer leaves, and in exchange you can work anywhere.
Acrylic metal is the practical choice for figure painters and for finishing touches on a model that is otherwise done: a gilt buckle, brass fittings, a steel blade. It convinces less over large smooth areas, because a brushed film works against the metal illusion; there a sprayed lacquer such as Alclad II from AMMO is the better answer. Matching opaque colours are in AMMO of Mig acrylics, and the full set of metal types is in metallic model paints.