Google announced yesterday that the Home device would be able to pick up and identify multiple speakers and access their accounts. While the Echo can be used to switch between multiple accounts, speaker recognition is a great for avoiding the manual process or clunkiness of switching between accounts.
This is the first step (or maybe second step) towards the ubiquity of voice as an interface. The next step after this would be to open up the speech recognition to any Google Assistant device. Essentially, these would be the portal to your account on Google.
It does raise potential security concerns about spoofing of voice. This is going to drive the need for two-factor (or more) authentication for interaction, especially for accessing any personal data.