Everything is backed up, BUT, they are all tied to a specific device and Apple ID. So can get the cards but need to set up the destination device as new, basically, and re-verify the cards. As
@gwang73 said, sign out of Apple ID, passes, and cards are marked as invalid.
iOS and watchOS can render cards unusable with Apple Pay on iPhone and Apple Watch.
support.apple.com
Apple has a support page for the specific pass, but the pesky Apple ID gets in the way.
Add a Suica, PASMO, or ICOCA card to Apple Wallet on your iPhone or Apple Watch to ride transit and make purchases using Apple Pay.
support.apple.com