The reason why it is superior security to a physical card is that a hacker can't find out your full card number. You don't even see it when you pull it up on the phone screen because the numbers are blocked out. Therefore all those folks who had their credit cards hacked at Target wouldn't have been hacked if they had used Samsung Pay instead.
When you say you put “your card” info into Samsung Pay, are you referring to a credit card, a debit card, and the number associated with such an account? In such case you use an existing account you have, as opposed to setting up something such as a Pay Pal account?