Answer:
To help keep your code organised/understandable by other people.
Step-by-step explanation:
One of the worse things if you are looking back at your code in the future is not being able to know what your code sections are for right away. You will want to make sure you explain what each section of code does for your own personal help. I'm not saying its required to do, you should probably do it to help yourself or other people who are going to read/collaborate on your code.