I didn't down vote but I think the clarification for "deep debt" would not include a low interest home mortgage or a car payment which you can also get as low as 0% interest on. Also many people have a student loan debt that can easily be paid off in a few years.

On a side note, I think all the above are excellent ways of debt.

Right now you can get a mortgage for under 4%. Mortgages typically do not compound interest. So it makes more sense to dump your savings into one of many savings that pay a similar interest rate or higher & do compound interest.

Many car dealers have 0% interest if you want to buy your car & not lease.

Of course any education debt that gets you a salary much higher than the debt makes sense as well.