This is particularly prominent in mortgage products. Traditionally, in the United States, the majority of borrowers had mortgages with fixed rates and equal monthly payments that were sufficient to cover the accrued interest and pay down the principal.
While nontraditional mortgages, including "interest only" mortgages and "payment option" adjustable-rate mortgages, have been available for many years, they were largely designed for higher-income borrowers who needed payment flexibility. The initial lower monthly payments make these mortgages attractive to borrowers who expect their income to increase. Payment flexibility also provides benefits to borrowers with seasonal or irregular income.