The primary purpose of using tin would be due to the economical price point in comparison to gold or platinum. Beyond the cost, the excellent solderability and corrosion resistance are the definitive properties of Tin that many industries seek. In addition, Tin also possesses moderate conductivity, adjustable appearance (dull/shiny), and FDA approval for food service.
A barrier layer/underplate such as Copper or Nickel Plating will enhance its ability to minimize migration of Alloying metals like Zinc into the Tin deposit. Last but not least, Tin is soft, ductile, and malleable. Its ductility allows a Tin coated sheet to be bent and formed without damaging the Tin deposit.