I don't think many systems are set up to handle them (Reg. Z disclosures plus individual state requirements) without additional programming and they are of limited use to consumers compared to widely accepted credit cards. It was cheaper to outsource a credit card program than build necessary infrastructure.
Where you do find these products, are revolving lines accessed by special check. We have such a product but have the minimum line set at $30M to keep it over the Reg. Z coverage. (This may get messed up though if a proposal I read about passes. It wants to raise that $75M or some higher number as I recall.)
My opinions are not necessarily my employers.
Rules and Regs minus Relationships equals Resentment and Rebellion. John Maxwell