I'm not a security expert, but I really don't think "a living thing walked through the ticket stall" counts as a second metric. A couple of more general object

I'm not a security expert, but I really don't think "a living thing walked through the ticket stall" counts as a second metric. A couple of more general objections: First, you're assuming that biometrics can't be faked. This is not a safe assumption to make -- most biometrics can be faked: DNA, fingerprints, even facial recognition. It is entirely possible that gait recognition and vein patterns also fall into that category. In a world where biometrics can be faked, they are strictly worse security than a near-range NFC device, because your biometrics get broadcast all over the place all the time, you can't turn them off, and you can't easily change them if they get compromised. Think about why social security numbers are so bad for security. That same reasoning is why stuff like fingerprints are not a good authentication method except as a (very limited) second-factor. Second, security is only as good as its weakest link. Even if biometric authentication was more secure than an NFC chip, it doesn't matter, because you can't get rid of the NFC chips. Biometric authentication like gait analysis fails for people in wheelchairs, it fails for people wearing dresses, and it fails for anyone who stubs their toe or gets new shoes with different support. Regular people will need to regularly fall back on another authentication method, which is probably still going to be NFC. Biometric authentication works well when it's provided as an authentication shortcut. The real authentication on my phone is the password, but because I'm not too worried about my phone security, I let myself bypass that password with a (less secure) fingerprint reader.