Being a sales person is like going to battle. Everyday you are in the trenches fighting fierce competition and doing what you can to survive.
The words you use are your weapons. They are what you use to grab the prospect's attention, to build relationships, to position yourself ahead of the competition, to defuse objections.
The better your pitch, the sharper your weapons are. If your pitch is not tight, it is as if your blades are dull. They may work a little and kind of get the job done, but you are not going operate at a consistent level of excellence.