Within the US they’re widely accepted, just as Amex is. A lot of merchants hate them because their fees are usually insanely higher. Outside of the US you’ll fi

Within the US they’re widely accepted, just as Amex is. A lot of merchants hate them because their fees are usually insanely higher. Outside of the US you’ll find dozens (dozens!) of merchants that accept them, while Visa and MC are nearly, if not totally, universal.