Not sure why you're so insistent this is a non-problem (to the point of implying that I or my housemates have personality issues, much less) - it's not like we haven't tried cash. It sucked, so my housemate made an app, and it's awesome.
> Do they go grocery shopping?
Not really - in college most people relied on the meal plan. At the house, we make heavy use of Amazon and Instacart. Those who do shop still don't enjoy having to remember to get cash and make change.
> Sounds like a personality issue
People forget, or just forget to grab cash, because it's not something they normally do, and no one enjoys playing debt collector. WePay can hold balances, too, so the app is basically just a more convenient version of the whiteboard, but with the extra feature of saving a trip to the ATM.
If obtaining cash was somehow related to a personality issue, but that person was otherwise a good housemate, it'd be worth it to throw some technology at the problem and make it a non-issue.
> checks
People are more likely to have a computer, so there's no need to add paper and OCR into the mix when there are better options.
> and then pays 4%
Only if the retailer is passing the transaction fee onto the customer, in which case they can pay with some other method.
People paying debts can link a bank account, so their transaction fee is maybe 50 cents.