That’s one way to think about them. You wouldn’t be safe driving without them. How would you know when to stop? When to give way to the other driver? Just try driving in a country without Road Signs and you know what I mean. It’s dangerous.
With punctuation, it’s a case of meaning–knowing that the writer actually meant to say. One recent famous case is “Eats, Shoots, and Leaves: The Zero Tolerance Approach to Punctuation” by Lynn Tauss. What does that sentence really mean? Did he eat, shoot and then leave? Or….and here’s what we find out…It’s really “[the panda] eats shoots and leaves.” That’s what keeps him alive…So, you see, the punctuation really did makes a difference. Those commas in the original phrase tricked you.