I wanted to know the advantage and disadvantage of accepting cash for payments.

Homework?

Yes it is.

This is not an answer, but a way to help you to figure out the answer.

For instance: If you are self-employed for a living and need to be accountable to others for tax purposes, what would be the advantage of receiving payment in the form of checks for the work that you have performed, if you need to show others the amounts of money you have been paid?

Right now, I am entirely self-employed. If I have to prove to someone how much money I have earned, how am I going to do that if I only receive payments in cash for the work that I have performed? Wouldn't I be likely to get in trouble for not being able to report and prove how much I have earned?