What would the benefits of NFC cards be? To me it seems more insecure given that anybody walking closely by could theoretically communicate with the card.
Typically for most keys used over NFC there's still a PIN challenge or some physical interaction with the device. There are some exemptions to this for usability (e.g. building access keys stored in PIV cards or the PIV applet in yubikeys), but in those cases too the keys are segregated by type to prevent misuse.