It’s no secret that you can buy things on the Apple TV via stores like iTunes or apps like GrubHub. However, unlike the iPhone, iPad, and Mac, you cannot use Apple Pay to purchase these items. Instead, you have to either have to have the payment go through your iTunes account or type in your credit/debit card information when making a purchase.
In all fairness to Apple and other companies, they do at least make you sign in to your account before you can buy something and try to implement Amazon’s “one-click and buy” method.
The way how Apple could implement Apple Pay into the Apple TV is by adding a little adapter to the Siri Remote. This would be similar to the Lightning to 30-pin adapter for iPhone, iPad, and iPod Touch. Anytime you want to make a purchase via Apple Pay on your Apple TV, plug in this adapter to the Siri Remote and you could do just that.
This does make it sound like Apple is making customers buy adapters and dongles for their products, which are not only expensive but also unnecessary.
Of course, Apple could always make a new Siri Remote, sell it as a standalone accessory and also have it in “newer” Apple TV’s (perhaps release it with a new 4K Apple TV?). It’s just another way to bring Apple Pay to another device.