I luckily don't rely on businesses taking cash, however, I think many people do, in particular the elderly and those who are on the absolutely lowest incomes as they would eek money out to pay bills by taking cash out at beginning of the week and I think this should be easily facilitated. I think it will be terrible if we lose our access to cash. I think the following should always take cash:
supermarkets
convenience stores
the post office
childcare provision, toy & book stores
pet supply stores
charity shops
budget shops such as Poundland, Lidl & Aldi
car parks (esp. hospital ones)
hospital canteens