A question about balancing a checkbook?

The point is to know for sure how much you have left in the account. Balancing the checkbook will also show which checks have not been presented for payment yet, so you can make allowance for those when you are budgeting the remaining funds. If you don't do it, you could think you have more "clear" funds than you really have, and you could end up in the red - leaving yourself open to penalty fees and high interest charges.

The banks make millions. If you do your sums right (and that includes balancing the checkbook) those millions don't have to be from you.

Because banks are responsible for keeping their records, they are not responsible for keeping yours. Because banks make mistakes and so do you and there is no way for you to know if you don't balance your checkbook. You are basically turning your money over to them and trusting them to look out for your benefit and assuming you don't make in errorin math or forget to post a deposit or check,....not the way it works.