I just used Android Pay in my local supermarket, on my Android Wear watch and there is no PIN involved, I have to use an unlock (I chose a pattern) and you unlock once you put it on your wrist then there is no PIN task as the time of use. It is a two step task, I press a button as I queue to approach the queue, then once items swiped then hold wrist to til.
Visiting UK soon and will try it there with my UK card…
As its practically impossible to lose it, as its attached to your wrist, it is a good way to pay for things in pubs. Also good in wet situations.
Personally I would prefer if we move to a more bio based method - looking at til or just be present and it auto debits like Amazon Go. If you may recall that used to be how it was done in some shops, you said “put it on my tab” to the shopkeeper and came in periodically to settle your tab, so there was not money authorization at the time of each sale.