There is a board for moist areas. Any drywall or home supply outlet will
have it. As for the plywood, it may not meet building code unless there
is
drywall under it. In a shop, plywood is nice in that you have one very
large tool board.

A good thickness of drywall will also let you hang "stuff". Good forbid
but if there is a fire, the wall board will definitely keep in one one side
or the other for a hour.