Commuter passes cannot be issued by JR’s Suica if the boarding & destination train stations are a competing private train-line’s station. Likewise, PASMO cannot be issued as commuter passes if the boarding & destination train stations are a JR-line station.
So employees are forced to use PASMO to get a cheaper fare, and can’t use Suica to do that in these situations.
Also, Suica doesn’t provide monthly commuter bus passes, whilst PASMO does.
Holy **** man… almost 20 years living in Japan and I had no idea regarding private/JR lines! Thanks for the explanation.