GM Motorsports executive director of competition Dr. Eric Warren has helped lead the Andretti Cadillac F1 project and said the FIA has indicated a decision by July 15.
More ambitious teams on the grid is always good, and a proper American team (sorry Haas) will lead to more engagement in the US which should help growth. I know the Americanization of the sport is a controversial topic and I too am dreading the Las Vegas GP (though the spectacle will probably be great the track looks dreadful for racing), but I think capturing the American market will be important for the big teams to stay committed to the sport. It would also just be exciting to have more than 20 cars on the grid again.
Now we just need to get rid of Alpha Tauri, though sadly the sale doesn't seem to be happening.
Andretti is an established racing team that has already proven ambitious and successful in other disciplines, and has demonstrated a clear and strong interest in F1 specifically. Gene Haas essentially got talked into starting his team, is by all accounts not that invested and mostly cares about the free advertising for his CNC machines. I'm sure Americans would prefer a team prepared to invest money into the sport instead of one struggling to even approach the budget cap and resorting to cut the pitwall to three people to save resources.
Who on the grid does? Ferrari, Alpine, Honda, and Mercedes build engines, outside of that the rest of the teams are building tightly regulated cars. Andretti is one of the biggest names in American motorsport, they're attempting to bring in a new engine supplier and one of the biggest car companies in the world, and they have the money to do it. What more can be reasonably asked of them?
Luckily, there won't be any Alpha Tauri cars on the grid from 2024 onward! Although they'll probably be replaced by an exciting team such as "Red Bull 2" or "Red Bull Jr"...