It's the same for personal debt, right? I would never take out a loan unless I expected the present value of the thing I'm buying with that money to be greater

It's the same for personal debt, right? I would never take out a loan unless I expected the present value of the thing I'm buying with that money to be greater than the discounted cost of the loan. It might be awfully hard to quantify (what's the return on paying my hospital bill compared to not paying it, or in fixing my car compared to not fixing it?), but there is a return and you only took out the loan because you figured it was higher than the interest you're paying on the loan. Same exact argument as for government debt.