OK, so let's say you buy and sell crypto using DEXes, and take home your profit in the form of Tether (or another stablecoin). What happens if you want to spend

OK, so let's say you buy and sell crypto using DEXes, and take home your profit in the form of Tether (or another stablecoin). What happens if you want to spend it on things? You can't use Amazon, eBay or any supermarket because none of them take Tether - so you're left holding a bag of useless Tether. Again, what is the point?