The time will come when you will be able to walk into any shop, chose what you want, pay for it where you are standing, and walk out with it, without having to go through the nonsense of lining up. The same will apply to getting through airport security/immigration, into a concert, onto public transportation and so on. Each of these ‘transactions’ will happen in the background.
The time will also come when whom you are is enough to make all of these transactions happen almost seamlessly, and biometrics will be an enormous part of that. However, WHAT you are does not equal WHO you are, and that’s where biometrics vendors miss the point. No form of static authentication (of which biometrics is one, same as passwords) can encompass your entire identity. Your likes, dislikes, hopes, fears, ambitions, friends & family interactions, even your reputation. The things that make you human, and 100% unique.
Also, what biometrics cannot do is replace every other form of authentication in the near term. Certainly not the authentication of payments for example when you consider that all payment card schemes globally are united behind the PIN.