However, that's probably because I live in a debit-based country. Debit cards without overdraft capabilities should be readily available even to people with no financial skills because you can't use them to spend more than you earn, making the risk to the banks themselves minimal. The small fee paid for banking services is the only thing at risk and even that won't have much of an impact on the bank in general.
Some countries, most importantly probably the USA, almost exclusively operate on credit cards for digital money, which are practically quick instant loans that you don't want to think about. There's very little in there to limit your credit card spending to your actual income and some people are foolish or desperate enough to borrow money to pay off loans, with credit cards being one of the easiest options. People with poor or no financial skills will run up a debt and quickly stop qualifying for credit, and the end result is that they're dependent on cash or even something as archaic as cheques to transfer money in stores. The extreme impact credit scores can have in the States is mind boggling but it almost looks like people accept some shady third party evaluating their entire life for fraud risk as a normal thing.
If your standard modus operandi is spending money that you'll have to pay back later, I don't think your society can be cashless. Normalise debit cards as standard payment systems and almost everyone can qualify. Frauds will find themselves struggling to get an affordable bank account, but in a modern banking system there are plenty of alternatives available.
Based on this article, Canada clearly needs a banking overhaul for any cashless ambitions to stick without dire consequences.