It’s a scam that:

0. for many aspects of life you need positive credit history to live at all

1. debit cards don’t help you build credit

2. secured credit cards (your own money! not borrowed!) do

3. both function almost the same way, but the latter is much less equally available

And if you think “living on borrowed money is a fraud”, I suppose that means you think only independently wealthy people should own homes? Nearly no one could afford to buy a home anywhere without a mortgage.