Q&A: A look at Samsung Pay, other mobile payments
Samsung Pay can mimic the old-school, magnetic signals produced by card swipes.
Plastic credit and debit cards aren't difficult to carry around and hand over, so there isn't an urgency to sign up for any of these services.
[...] while Samsung Pay works with more merchants, acceptance isn't universal because of technical and behavioral constraints.
WHAT ARE THE DISADVANTAGES?
Because Apple Pay and Android Pay require NFC payment equipment, there's a good chance it won't work where you're trying to buy something.
Despite promises of wide acceptance with the magnetic technology, Samsung Pay won't be universal.
The technology also won't work where you need to insert your card into a machine, such as gas pumps and ticket kiosks.
The service will initially work with just four Samsung phones — the Galaxy S6 or S6 Edge from this spring and the upcoming Note 5 or S6 Edge Plus.
Android Pay can be used within selected apps for online transactions, so you don't have to re-enter card numbers and shipping addresses.
With NFC, the phone can detect when it's near a payment terminal and automatically launch the payment service.
Because Samsung Pay has a magnetic component, which is a one-way technology, you need to activate it first by swiping from the bottom.