> Well, there's this crazy concept called "saving money" where you don't borrow from a bank but rather put some money aside every month to be able to afford something expensive
I think the point here is opportunity. You might be able to afford it in X years and pay no interest, which of course is better, but you may also have to act "now". This is where credit is adequate and needed.
Also: time. Imagine a fellow (me, as a student) who hasn't got a washing machine and does his laundry every other week at the coin launderette, which takes several hours, including the time spent on public transport. They could save up the several hundred bucks for a washing machine and buy one in a year (student, limited budget, or just simply poor), or buy one on credit now. As soon as the thing is installed you have two more afternoons each month to get more productive work done. What would you choose?
I think the point here is opportunity. You might be able to afford it in X years and pay no interest, which of course is better, but you may also have to act "now". This is where credit is adequate and needed.