In addition to having a user record his voice data, the Google Assistant does not allow any other interaction with device, from Lock Screen. In addition to general questions, most phone features, such as making a call to one person, are blocked until the owner unlocks the device.
It seems, however, that in the near future, Google intends to relax its strict rules on the lock screen. The 9to5Google made an A / B test, showing the Google Assistant Beta (10.28 version), sending a text message directly from the lock screen.
Now a "send message" option is displayed, which allows the user to send one sms, even when the device is locked. This feature is also shown in the following screenshot:
While still in the A / B test phase, the feature is not available to everyone. For example, while trying out this new feature on Pixel 3 running Android Q, he was still requesting "Unlock for Resume". At this time, it is not certain whether this new feature will be released to the general public.
However, if Google decides to release this feature for the public, will undoubtedly raise many concerns about it protection of the private life. Google Assistant still has a weakness in voice recognition. This weakness could enable third parties to send messages from users' phones without their consent.
While voice commands are convenient and effective, Google and other companies that offer this kind of digital assistants, should focus more on the balance between private privacy and feature offerings.