I'm not even sure I see the economic viability of payday loans/microfinance even in the best case. Certainly not if you are running a private business based on that. If unreliable income caused you to need a loan in the first place, I'm not sure how a usually high interest loan helps in the long run. So maybe they are not intentionally scams but the outcomes are very much the same
The problem with payday loan companies is that they give access to loans to people who cannot pay any type of loan back. If they had enough money to pay e.g. their credit card bills then they wouldn't need a pay day loan in the first place. Most payday loan companies have a smaller borrow limit most credit cards or even regular bank accounts in europe.
Now imagine you are running a company that is making a profit by lending to people who cannot pay their loans back. Isn't that impossible? Shouldn't your company lose a lot of money because it's handing out money but never getting it back? You are forced slap on all the lost money as extra fees on top of the loan itself.