I would say it's very important, if your dog ran into the road and caused a car crash you would be liable and that's what it would cover. I was assisting the police last weekend as two dogs had ran out an open door and attacked a driving pony that was waiting at the junction outside, the horse bolted causing damage to five parked cars, injuries to both people as the were thrown from the cart and the pony plus a wrecked cart. Hate to think how much that is going to cost!