Wow! We got that wrong. I thought it seemed extremely powerful to stop a spell and then get a free transaction.
In another thread I also noticed that we only allowed one interrupt and that went clockwise around the table to the first person who used his interrupt.
This will make things much more fun.
Yeah, having your spells canceled would be no fun at all!
The interrupts just allow you to make a transaction when it's not your turn. It's still powerful to have active, as it can give you an "out" if someone casts an unexpected spell that is about to ruin the value of your holdings, or it can just plain allow you to make a transaction at a more opportune time than was available during your turn.