What is rent reporting, and what is one major limitation of using it to build credit?

Rent reporting services like Rental Kharma, Boom, or Experian RentBureau allow renters to have their on-time rent payments added to their credit reports. The limitation is that FICO 8 — still the most widely used model by lenders — does not score rental tradelines, while VantageScore 3.0 and 4.0 do. This means rent reporting may boost a VantageScore significantly while having little to no effect on the FICO score a mortgage lender will actually use.