Like, when Unilever launch a new detergent, they give it a totally separate brand. If it fails, they drop it quietly, and if it succeeds they can roll it out worldwide.
I wish Google would do the same. Launch this as 'allo', with the fact that it's from alphabet buried in the small print. Once it's been doing well for a couple of years, they can think about pulling it into the Google brand and pushing it to every user in the world.