Thanks for all the answers.
Couple of more clarifying questions - what model Samsung phone(s) have you used and which was the model giving most trouble (either MST or NFC)?
Second question, regarding this:
Card terminals that require you to insert the card vs swiping (gas stations and ATMs)
This is what bothers me - all my cards are chip based. Last year I had several cases in Starbucks and Target when I tried to use chip card at the terminal where chip reader was disabled or non-operating. So when swiping, terminal was saying 'insert card' - catch22, basically card was unusable.
Now, seems that if terminal has chip function disabled then even MST mode will be no help.