Debt is debt. It's net benefits to society are zero sum, for all but the bankers.
Which is pretty much bollocks. Debt is one of the most powerful economic tools ever invented, rivaling money itself. Like any tool, it can be used well, or poorly. It's basically never a zero sum game.
On a larger level, debt is still tomorrow's demand, spent today.
Sorta, but not really. Debt is a type of mutual bet made by the investor/banker and the beneficiary that the value of the assets purchased by the debt will exceed the value of the money the debt reflects. And most of the time, it works out, and everybody wins!
Let's say I need $100,000 to buy new injection molds for my business in order to build a product. Without the $100k loan, the injection molds never get built, and at the end of a year, you have $100k in cash still sitting in the investor's hand.
But if the injection molds get built, and the product sells, you have:
A) The investor no longer has $100k in his/her hand, but they have the debt, now somewhat greater than $100k. (interest)
B) The borrower has $100k in debt, offset by the value of the new injection molds, AND the profits made from the product created with the injection molds.
This scenario is a positive sum game. Personal debt is an entirely different matter.
Like before, you are making a bet with an investor, and it does sometimes work out for the positive, but consumer debts are typically used for things to consume. If you spend it on a house, a house can be built that wouldn't exist otherwise, so it's probably a good deal. If you spend the money on hookers and blow, you truly consume the money and have no assets to "win" on. Now you have interest due on the money, which is economic activity that won't happen. Money spent on interest is then NOT spent on "real" goods, and everybody loses. Even the lender loses some, as the overall economy is damaged, even if this loss much less than they gain in personal interest money.