Sure, plat makes a lot of sense in a number of province cases:
1. Space efficiency. Plat takes up only one card (and requires only one buy) so you can more easily build engines.
2. High variability. Take a simple card like cellar. Plat makes it a lot easier to go for a high cycling/sifting strategy and pitch cards until you get back to the plat. With gold, you need a 3 card residue to get a province, with plat you need only 2 - so pile on the warehouses, grab a storeroom and hunt for the plat.
3. Plat has some good interactions with a number of action cards that can let you get major benefit out of it. Mint/Mine both give you relatively more reward from Plat than from Gold; both also have a much easier time piling out the Plats than the golds. Plat is immune to Noble Brigand, Rogue, and Knights. Herbalist/Plat is an assured duchy, and a highly likely Province; being able to get that close to a Province repetitively is a lot stronger than using gold.