It is almost entirely mortgage debt backed by the collateral of housing.

Not the most productive asset to be leveraging, especially in rapidly declining birth rate countries, no?

Meanwhile, while headline credit card interest rates in the US look insane (like 20%+), in reality loss-adjusted yield actually realized by lenders and paid by consumers (after renegotiated settlements, bankruptcies, payment plans, etc) is less than half that.

You can look at the realized return on personal credit lending on companies balance sheets, its basically like 3.7%. Maybe a few percent more return than what a 30 year mortgage lender can expect going forward (now that we're returning to post-GFC 'normalized' interest rates).