Stainless steel is a product used world wide, allowing products to made from a material that has high Chromium content, making it an excellent protector for corrosion.
Stainless steel has twice the tensile strength of mild steel, due to the other elements in the metal, now if you have an area that is constantly wet and you use mild steel, the product will have to be replaced due to the quick erosion of the mild steel. Now manufacture the same product from stainless steel and the results are a different story - the stainless steel unit will need to be replaced possibly due to a fork truck accident rather than corrosion.
Now should you have the application were an outdoor digital sign is being installed near salt water, in a wharf for example, the ideal solution would be a stainless steel LCD enclosure. These protect the digital signage hardware from the hostile areas including the sea salt that would corrode mild steel enclosures.
Normally, the application would be in an un-manned area, so physical security would be required, to protect from vandals, now the ideal solution that will protect from every thing nature can through at it, is an LCD enclosure, these units comply to NEMA4x and Ip65 standards for electronic enclosures.