Pretending to review is worse than not reviewing. We are not reviewing, and you need to trust the publisher just like in any other packaging publishing platform. If you are using a deb published by Google (in a repository or otherwise) you need to trust Google. If you are using a snap published by Google, you still need to trust Google.
That may sounds uncomfortable, but that’s exactly the situation you are already in no matter your choice of Linux, with or without snaps. If you are only using official Ubuntu repositories, you need to trust Ubuntu developers. If you use snaps that are only published by Canonical or snapcrafters, that’s who you are trusting.
The difference is that instead of asking people to host their repositories elsewhere, PPA or not, we have a convenient and integrated publishing platform, and also that we improved the packaging technology, including confinement strategies.
Please let us know if there are any other questions we might help with.