Google has several options for intelligently locking your home screen already, including trusted places or devices.

Now, its adding a new option: trusted voice.

If you say Ok, Google, your phone can unlock, but someone elses voice wont unlock it.

Smart Lock is a convenience feature more than it is a security feature.

If someone has a recording of your voice saying Ok Google, they could theoretically unlock your gear.

If its showing up for you, try it out and let our other commenters know how its working!

Functional Trusted Voice Smart Lock Option Rolling Out To Some Users| Android Police