JR West joined Apple Pay on March 12 with their J-West VISA, J-West Mastercard and J-West JCB credit cards. The cards are on the QUICPay payment network (the spiffy updated Apple Pay on QUICPay page is worth a glance).
Now that JR West is playing nice with Apple Pay the big question is Apple Pay ICOCA next? Definitely maybe, especially if the Apple Pay China Transit signs spotted in iOS 11.3 beta 4 point to easier transit card support.
I have posted about ICOCA getting ready for Apple Pay, here and here, but so far there is no sign that JR West has the necessary cloud service in place yet for that to happen although SMART ICOCA is the beginnings of one. Then again JR West has much deeper pockets than say PASMO. They can certainly afford to cut a data deal with JR East Mobile Suica or build their own.