When I sold on eBay and they allowed cash/bank draft payments, I accepted local currency, but also major currencies like US$ (in cash or bank draft because I had a US$ account too) and other major currencies in cash (like EUR and GBP) because they were cheaper to convert with when travelling (or I could use directly). Without a spread.
Plenty of places in the world accept currencies besides the local ones because they are more stable or just worth more in general. Depending on the business, they might handle currency the same way too.
Used the EUR in Cuba when a buyer mailed me cash.