yes watch batteries are different from regular batteries because watch batteries are much smaller and hold less electrical charge. they would not work in anything else other than a watch.
Ni-cad batteries first became popular as portable rechargeable batteries. The "regular batteries" used in cars are mostly lead-acid rechargeable batteries. The "regular batteries" used in toys,...
With the same load current the AA will last longer that the AAA. This is due to the physical size of the cells. A C cell will last longer that a AA and a D cell will last longer that a C cell. In dry...
Use the internet or the phone book to locate local watch shops. This way you can ask a professional which battery is right for your watch. You may also compare prices.