"...in every historical hyper-inflation event I've read about, people still did most of their trading in cash."

To some extent, yes, but in those times, most people aren't buying much. Yes, if it takes a wheelbarrow full of money to buy a chicken, and your truck payment is $600, you might not have any problem making your payment.

My Mom was young teenager in a series of mining towns during the Depression. She said that while the richer people (relatively speaking) did have money and did spend it, most of the people her family knew were trading and bartering services. Her mother had chickens and traded eggs and an occasional live bird. A man down their street had three milk cows and a steady stream of customers, some trading vegetables, firewood, housecleaning, etc. Most people had wood cookstoves, so firewood was always in demand. Some women took in washing, some took in boarders; some of the boarders paid in labor.

My grandmother heard that a man nearby was going to burn down two still-decent sheds, so she hurriedly made a deal with a man who had a tractor. She said she would remove the sheds from the property (with a few live chickens to seal the deal); for hauling one shed to her property, she gave the tractor man the other shed; she used her shed as a coop so she could raise more chickens. She worked part-time at a restaurant and brought home the leavings for the chickens.

Trade and barter aren't dead, just dozing.

Sue