AC is very lenient when it comes to automation, bots and the like. The bow dance was a fail safe method of making sure a toon was standing and not in combat. A lot of macros had you lay down to rest faster and no matter what state your toon was in, if you equipped a bow, the animation of that would force you to a standing non combat position. Thus a saftey reset if you like in case your toon was laying down but the macro wanted you to cast spells, or standing doing nothing because you were not in a combat state or vice versa. Later they came up with a 'bowless dance' But the effect was all the same.