Grace periods for other kinds of consumer debt
Other kinds of consumer debt, especially mortgages, car loans, and personal loans, have grace periods that amount to a penalty-free window that allows you to make a late payment. It's not really a late payment since it's during your grace period, of course. This can help people who may not get paid on set days of the month but instead are paid every other week or the first and third Friday.
Grace periods are beneficial for you as a consumer since they give you more time to make your payment without denting your credit score if something comes up. As with other debt, make sure to check your loan agreement for the full details on your loan grace periods, as they aren't always the same.
In the real world, borrowing money to buy a car is a really common situation. But if you get paid on the 20th, and your car payment is due on the 19th, even a short grace period can save your bacon (and your credit score) by giving you the flexibility to pay when you're able.