Good Debt vs Bad Debt

The useful test here is arithmetic rather than moral. Borrowing adds to net worth when the return on whatever it financed exceeds the interest paid for it, and subtracts when it does not.

Mortgages and student loans often clear that bar: rates are comparatively low, terms are long, and the thing financed either appreciates or raises income. Revolving balances at 18 to 29% rarely clear it, since very little returns that much reliably, and the purchase behind the balance has usually already been consumed.

Notice that the rate is doing most of the work in that comparison, not the category. The same car financed at 4% and at 15% sits on opposite sides of the test, while the label on the loan never changes.