After the beep btw, NFC and MST are automatically turned off. It's my favorite way to explain to people how it works and to spread the word.
I enter the default pin of Samsung Pay (because it's giving the merchant a virtual card number and not my real card info) and I get a shocked look from the clerk while they hand me a receipt. I pass the phone over the credit card slider and it beeps. Then when it's time to pay I take out my phone, swipe up without unlocking the screen (been a feature for a couple years) the app automatically turns on NFC & MST and you press your thumbprint to begin a 15 second countdown. There's always a clerk who says they don't take mobile phone payments. I go to little markets and mom&pop grocery stores that don't have the NFC pads. I choose security and the added convenience of being able to pay at places that don't have NFC capabilities. It does come down to a matter of convenience vs security for most. I have been using Samsung Pay since it first was available on a Note and I've always been on the side of the fence that MST has been the better experience.