Have seen it first hand
Several years ago when I was running my own small internet based business, we were hit by hackers that took over the site and covered it in pornopraphy. Since a lot of our web development work was outsourced, it meant massive delays in getting the problem fixed, especailly when our usual person wasn't able to shore up every hole the hackers made.
While it took several days to get our business back up and running, the worst part was that it made our customers vulnerable. No good. Digital security is a must, regardless of your business size.