Privacy and identity protection aren't the only uses for biometrics devices. They're also invaluable as medical tools, capable of keeping track of things like heart rate or blood pressure. Perhaps the best all-in-one such device is Scanadu's Scout, which can read essential biometric stats such as blood flow, blood oxygen level, electrical heart activity, temperature and heart rate. And it does it all just by placing the device against your forehead.
It's almost reminiscent of the fictional medical tricorder device often wielded by Dr. McCoy on Star Trek.