Haggis they are both mechanical watches. Either hand wound or automatically (self-winding with a little weight that freely spins and creates spring tension as opposed to you winding the crown to create spring tension).
The relative merit is 1) that it is (usually) something that has has more care put into it than something which runs off of a battery. 2)Geeky in that you have a little mechanical machine beating away on your wrist whose sole job is to count very very accurately. 3)Beauty 4)something ultimately inconsequential and useless in today's' world that you can spend stupid money on just because.