One glaring weakness of the Japan Transit IC system is that it’s not universal even on the very rail networks that built the system. Suica for example is mostly absent in stations outside of Tokyo, Niigata and Sendai metro regions, roughly half of JR East stations. It comes down to cost: hard wiring every station is expensive. This cost problem is one that JR East plans to address by rolling out a cloud based low cost ‘simple Suica’ for all stations. They already missed a 2020 deadline and need to deliver on their promise if Suica is remain a viable payments competitor in the hyper competitive Japanese market.
JR West meanwhile is busy expanding ICOCA coverage on the their rail network with Fukuchiyama and Kisei line additions going online March 13, 2021. JR West also added ICOCA connecting commuter passes for Osaka Metro in December, the kind of arrangement that Suica and PASMO have had in place for years. It makes sense for JR West to expand now in preparation for the Mobile ICOCA launch in 2023.
The Kisei line is somewhat unique in that smaller stations are unmanned and local trains are one man operations with passengers getting off at the front for ticket verification. ICOCA readers are located at car exit points, passengers tap out similar to using a bus. This kind of operation would fit well on similar ‘one man’ operations like the JR Central Minobu line which are still limited to paper tickets.