According to the IOTA documentation, the coordinator (aka kill switch) is to prevent certain types of attacks related to double spending. IOTA does not have any miners, and it does not cost any coin to send a transaction (only a trivial amount of POW effort), and there is the risk that someone could do something very similar to a selfish mining attack that does not cost anything to try. 

The way I read the documentation, I don't think the coordinator was intended to be used as a kill switch, or more specifically, this is not how it is presented.

I don't like the use of a centralized validator, and would not trust any coin that uses one. It appears they are rolling back the IOTA blockchain to reverse the transactions involving the stolen coin. Etherum did something very similar in it's early days when a hacker exploited a flaw and drained coin out of the DAO, although it has something resembling consensus before doing this.