The watch connects via bluetooth. Nfc only replaces the procedure for connecting and setting up the watch. Ie you turn your bluetooth on then use the nfc tap function to connect the devices. If paired it will of course connect automatically without the touch but not necessarily straight away. The bluetooth shouldn't use much battery as it low power bluetooth 4.0.
---------- Post added at 10:00 PM ---------- Previous post was at 09:59 PM ----------
Essentially the nfc replaces having to use a bluetooth pass code of some kind.