It was already explained in another thread, it's a security measure (of rather dubious quality) they put in for when price is falling too fast. This is the kind of "solution" that makes software engineers around the world scream out in agony.
How is this a better idea than simply halting trading?Quoted. IMO, manipulation in ANY way is wrong. If it has to fall, let it fall. But if you want, just halt the trading, it is the best choice: but they can't steal if the market is closed
