None of this solves the simple visual of "I'm running out of cash in my wallet, better slow spending down"
I could log in to my bank online and check, I could keep a mental tally of "I spent this here and that much there, I should have this much...", but both of those are decidely more work.
Furthermore, every time I switch back to cash (and my fiancee has independantly noticed), budgeting and saving gets easier. Once again, likely because of the visual and tactile nature of cash
Most damning of all, guess how well credit and debit worked during the multi-day Rogers outage a few years ago. You say "That was a once in a lifetime fuck-up", I'll say "That's not the only reason or time stores haven't been able to process cards"
I'm under 30, and I remember grocery stores around holiday time being unable to accept anything but cash.
Electronic systems aren't actually a solution here. We have a solution, it's called cash; it does not rely on what is essentially a duopoly (Visa/MC), it does not rely on asking permission from a handful of gatekeepers (for-profit banks you'd like to transfer to/from)
Credit unions aren't the solution to the latter either - you can use one, but anyone you're trying to pay is almost certainly with a bank.