Visa's payment-enabled sunglasses are ready for the beach

Tap-to-pay terminals make it easy for you to pay for things with your smartphone (hey, Apple Pay!), so in theory, you can use them to pay with anything that can support an NFC chip. 
That’s what Visa was illustrating at South by Southwest through their latest payment-enabled accessory prototype: a pair of sunglasses. The sunglasses had a small NFC chip embedded on the side, which was linked to a pre-paid card, and you could use the glasses to pay for stuff wherever tap-to-pay was acc