Unfortunately, the Voice Match feature is not enabled on my phone, but there is a Google Assistant help page that guides you through the setup process if you think you might have it.

If you are able to get to the set-up screen, take special note of Google’s ‘Keep in mind’ message: “Someone with a similar voice or recording may be able to confirm purchases on devices you’re logged into.”.

I can see how this feature could be beneficial to individuals with a disability that would make it hard for them to confirm purchases with a fingerprint or a face scan.