Using yourself as a credit card, wallet, password, entry into all of your private real and virtual lockboxes etc. is all very convenient, but you've centralized your whole identity. So what, you say, only I have my fingerprint/face/retina, whatever? Nobody can steal my uniqueness!
For the moment, maybe not. Right off the bat, I can think of two ways to hack your biometric identity. The first would be to hack into the central biometric data repository and simply replace your data with someone else's. That person would then steal most or all of your wealth, after which the data would be switched again to cover the tracks, probably before anyone knew a thing had happened.
The second way would be to secretly photograph whatever part of you was being used for biometrics, in extremely high resolution, as a blueprint to create a prosthetic device which could then be worn or, in some circumstances, simply waved in front of a scanner to gain access to your life. Worn prosthetics could include a realistic synthetic skin glove, a Mission Impossible type mask, or a contact lens. Science fiction movie magic? Only a step beyond biometrics itself.
Finally, whatever safeguards are promised at the beginning of a biometric revolution, try to realize that sooner or later people in the government are going to be tempted to use all that information which has now been tied to one single, unique piece of data, what database programmers call the primary key, the one that opens up all of your privacy and your personal power.