There are only two reasons to own a 16 ga today: you have found a properly scaled gun built in a 16 or 20 vs frame so it's a light and dynamic gun, and it's a deal.
As noted above, up through the Fifties, 16ga was very popular. The "square load" and the lighter-than-12 carry made it an ideal upland bird gun. If you can find one of the American classics so built, a Parker, an LC Smith, a Lefever, a Winchester, or an Ithaca for example, it's worth it. A clunky, tank-built 16, or some semi-auto built on a 12 ga receiver? Why bother? Get a 20 that has all the benefits plus a vast range of cheap ammo.