Rent payments are used to formulate your FICO 9 score. Your rental tradeline is also used in different scoring models, such as Vantage, and can be used to make credit decisions for lenders who look at more than just your credit score.
Rent reporting builds history in your credit file without adding debt. Because rent payments demonstrate responsibility, and the ability to make large on-time monthly payments, the scoring models take that into account.
Remember, credit is all about demonstrating history. So, typically, the longer you have a rental tradeline on your credit report, the better.