Why don't Bangkok laundries accept USD or EUR cash?
Two practical reasons. First, exchange rates fluctuate daily, and a small business can't afford to set rates that hold for 24-48 hours of a wash cycle. We'd lose money on currency drops. Second, banks charge 2-3% to deposit foreign currency, which would force prices up for everyone. Most Bangkok ATMs and currency-exchange kiosks let you withdraw or convert THB easily — generally cheaper than embedded laundry markups would be. We do accept the modern equivalents: card, PayPal, PromptPay, Wise.