Actually, it is Samsung who purchased the company had the patents and the hardware to allow for use with magnetic strip terminals.
You don't have to choose which method within the app to use with Samsung Pay as both NFC and magnetic strip methods are activated by opening the app. If you want to use magnetic strip you put the phone near the strip reading slot, if you are at a Tap n Pay reader you tab the appropriate area on the reader, and it has a card chip slot you put the pone by the slot, and let the magic happen.
The Android Central Samsung Pay Forum has lots of good information by some very tech savvy folks concerning this.
I went back and re-read my post, and I didn't mean it the way you interpreted it. . I know the basics about Samsung Pay, and how it works. By choosing, I only meant how the technology may work, using NFC or LoopPay, in that swiping up enables whatever it's pushing out of the phone, allowing you to choose between where you need to position the phone, depending on the terminal.
With Apple Pay you just put the phone next to the terminal near the appropriate area, and the phone automatically recognizes this. You then just authenticate with your fingerprint. You don't have to unlock the phone or swipe anything, just position your phone and tap your finger on the home button. This make is more easier and seamless from my experience..
Samsung pay would be even more awesome IMO if you could do it that way. Just position your phone in the appropriate area, weather using NFC or the magnetic method, and tap the home button with your finger.
The point I was trying to make was maybe Apple had the patent for doing it exactly that way, which is why Samsung doesn't do it. Or, since Samsung pay uses two different technologies, it has to be done the way they implement it (swiping up) I'm not sure. I will check the area on the forums you mentioned, because I'm interested in all that stuff and would like to know more.