I've just gone several months without access to any electronic money (e.g. debit cards, credit cards, phone etc) and it has been complicated. I've been thrown out of several stores at the checkout because they couldn't or wouldn't take cash.

You also lose the ability to take advantage of many special offers that are available only through retailers apps, e.g. McDonald's. You can get the discounts, free items, nor can you accrue any credit (e.g. Walgreen's Cash) or points towards future discounts.

I also couldn't ride any of the scooters or bicycles in my city that are available everywhere, because it is incredibly difficult or impossible to use cash to access these forms of transport. You can't even use your cash to buy a prepaid debit card as they won't accept prepaid debit cards to rent the items.