I think I read somewhere the psychological effect was greater on the enemy.
I used them, thought that was in 6mm and only because an episode of Sharpe had them and in 6mm they cost me less than a quid.
Were they lighter and easier to transport?
I suspect they never took off (ha ah aahha a oh erh cough ahem) as they were not as effective as cannon?
I am experimenting with rockets for my fledgling war of 1812 games. I view them more of a morale cause then destructive artillery damage. Also I want a feeling of never knowing where they will go and what they will do type of thing.
So roll two d6. On a 12 they hit the target, cause two morale hits and a casualty. On a 2 they explode on launcher destroy base. Other rolls will send emoticon various directions and leave morale markers ( on friend and foe alike) type thing.