Zelda was weird and impractical outside of the standard controls, but still somewhat benefited from NFC.
Splatoon plays a lot better with the motion controls, NFC is actually a nice QOL improvement. A game like Arms is also nicer in split mode, even if core players tend to get back to the standard controller mode.
I see it along the lines of the Allan Kay "People who are really serious about software should make their own hardware" quote. Nintendo should stay serious IMHO.
For Splatoon it's used to quickly switch to preset weapons and gears as well, which is nice. You widly experiment with your gear and instantaneously get back to your "serious" setting at any time.