It's primary use would make your pirate do a coin toss and come up either Heads or Tails. The secondary use would make your pirate show the result to others.
The main point in this is to resolve discussions within crew. So "Heads I'll steer, Tails I'll fish" or "Heads you dig up chests, Tails you guard the boat"
Every now and again, your pirate could even accidently drop it and it would cost 1 gold piece just for fun.
I'm sure us pirates could think of some horrid uses for it too.... "Heads we sink them, Tails we'll give them a Captains chest"
In between tosses your pirate would bite the coin if no action had been requested to make sure it really is gold

