The operation of Google Assistant already allows for advanced analysis of user's voice. According to Google, this system is already in advanced phase of development, so it will be used to verify the person making the payment by phone. This information has been confirmed by the manufacturer itself.
The new function called "Confirm purchases with Voice Match" will allow the recognition of the user's voice, which will later confirm payment in the applications. This feature is currently in the testing phase and will only work when shopping through Google Play and when making payments in restaurants. By default, new feature is disabled and if you want to check if Google allows you to test a new add-on, you can enable it manually in Google Assistant's settings.