True for banks. Payment use of NFC has been limited to use with Secure Enclave which is private. Use of NFC in Wallet has been around for key cards, transit, and other customer uses for years. Same with NFC use in automations.Apple has made this available to a few specially blessed/selected businesses (eg: certain transit operators have been given access to implement digital versions of their fare cards), but there is no generally available API to add NFC cards to Apple Wallet.
Certainly, no banks or financial institutions have been allowed to add their own NFC cards to the wallet as an alternative to Apple Pay.
I really have not looked into where the issue with broad transit card usage is - Apple restricting entitlements or the transit services supporting the NFC cards. Given that even the locations that are in Apple Wallet still are not universally accepted in the given transit systems strongly implies it is more of an adoption by entity thing than an apple restriction thing.