Having a strong 9-ball break is a very important part of being a good 9-ball shooter. Since making at least one ball on the break allows the player to keep on shooting, naturally you want to cultivate a consistent break shot.
Conversely, if you break and don't make a ball, you give your opponent a huge advantage. He takes over the table with the balls all scattered and ready to be pocketed.
The following video shows the correct procedures and strategies for breaking a 9-ball rack, and how to keep yourself out of trouble. The ideal break stroke is also described.