From the letter:

Interest rate limits are the single most effective tool states have to protect their residents from predatory loans. Predatory loans include payday and car title loans that often carry annual interest rates as high as 300% or more. Predatory loans also include high-cost installment loans and lines of credit with rates approaching and well exceeding 100%. These loans target financially distressed individuals, compound their debt burden, and leave them worse off. Payday lenders also disproportionately prey on communities of color, stripping them of income, exacerbating financial exclusion, and widening the racial wealth gap.