There are many ways to keep property secure, and there are also many ways to make security more convenient for those who desire convenience. One example is the voice recognition door lock. It is more convenient because it recognizes a voice as opposed to a key or an electronic card, and so these token do not have to be on the person to open such a door. At the same time, it is more secure because a voice is harder to copy than a key.
Imagine being able to open a door without carrying a key or a key card. There is no worry of a key ending up the wrong hands, and it is extremely difficult to duplicate a natural voice. Such a system is very secure as long as the electronic system is functional, and security of this sort tends to be hardened against tampering.