I do not agree with the idea that borrowers are the ones who gain from this, only a few borrowers who know very well what they are doing and who have a great capacity for self-control do so.
It just a real fact, it's practicable enough. Even the example given made it clear. Although the lender made some profit through interest but during inflation the profit will have lose It's value. Imagine the interest rate is just 3- 4% and inflation rate is up by 9% or more. This is happening here in Nigeria as price of good and commodity keep increasing everyday.