I had the same experience in Laos in 2019. Cash was needed everywhere except my hotel and restaurants that specialised in serving tourists. Needed cash for convenience store, tuk tuk driver, entry fees, food stalls, local restaurants, most shops - pretty much everywhere. As kip was a controlled currency at that time (maybe still is), there were limited places to get it and I under-allowed when I got my initial supply at the airport and had to use the hotel for a float - at the usual poor hotel exchange rate, but it wasn't sheep stations (should have put this part in the travel mistakes thread!). At the end of my trip, I had a bit left over - about AUD100 by my reckoning, even after I had left tips all round. When I went to convert it on leaving the fees etc were so steep that (from memory) I was going to get back something like $27. So I declined, and looked for someone to give it to. Found an Aussie couple about my age or a bit older in the coffee shop and we got chatting. They were heading up to Luang Prabang for a Vietnam veterans reunion, so I gave it to them and said buy some beers. They were very grateful. Plus I warned them to spend or gift it all before leaving Laos.