Yes, not all accounts will revolve and be charged interest, many will. credit card balances have been going up for decades: https://fred.stlouisfed.org/series/REVOLSL (This is ALL revolving credit, not only credit cards, but it's mostly credit cards). It's well over 1 trillion dollars now. Yes there are cost(s), but credit is a very strong and well run business now and is absolutely a profit center for banks. If they get too many freeloaders that don't carry balances to hit their income targets, they will add some fine print to curtail freeloader use-cases enough that they can hit their income targets. This has been going on for decades now.