Wasn't expecting it TBH, they seemed pretty reluctant from what I've read so far. Let's see how it pans out.
Edit: but wait, it seems it's not a done deal and still needs to be approved by the teams and the CEO ...

The teams shouldn't have any say in commercial agreements.

I think they'd be a quality addition to the grid. I appreciate the concern about the dilution of the prize pool, but wasn't that supposed to have been addressed by what was supposed to be a huge buy-in cost for new teams under the most recent concorde agreement? https://www.motorsportmagazine.com/articles/single-seaters/f1/what-is-in-the-new-f1-2021-concorde-agreement/

Awesome for F1, wonder how reluctant the other teams still are

Awesome, I'm excited to see how the next 10 years play out

Isn't this non-news in that we already knew the FIA were fine with it, it's FOM/Liberty/Teams that are actively blocking the entry, right?

Unpopular opinion/rant: I don't think this is good news for the sport.

Of course it is about the money. In a capitalist society, everything is about the money. And I do agree that in the case of Mercedes, Red Bull and Ferrari it is pure greed, but what about the rest of the grid. Haas and Williams are now viable without relying on paydrivers or shady sponsors. McLaren and Aston Martin have now the resources to compete for podiums. If teams receive less prize money, F1 would be undoing all the good progress of the last few years. Is it worth it for Andretti?

But wait, adding Andretti will for sure make the pie bigger! Of course, those people at FOM and the teams are dumb and haven't accounted for the trillions of spectators than Andretti will bring. Let's not forget that this year the viewership in the USA has decreased despite an American driver. And also that Nascar is way more popular than Indycar in the USA, so an Indy team like Andretti will attract less viewers than a Nascar team like Haas (and we already know that Haas didn't attract that many).

And then there is the anti-dilution fee. Which is literally a patch, it only covers for the first year. Once the anti-dilution fee is spent, we go back to Haas and Williams (and probably Andretti themselves) fumbling for paydrivers and shady sponsors, and McLaren and Aston Martin languishing in the midfield.

But at least we would have one epic year of 11 competitive teams, right? Haas was competitive from the start, and Andretti will use the same model. In the first place, will they? It seems that Renault/Alpine are only interested in selling them PUs and gearboxes, and nothing else. Second, the (very limited) success of Haas depends on Ferrari always being a top team, despite the memes; Renault/Alpine have been an eternal midfield team for almost twenty years. And finally, Haas relies on Dallara building their chassis even more than in Ferrari's parts. Andretti has zero experience in building a chassis, they only participate in spec or quasi-spec series, and the rules prevent Dallara from providing chassis to more than one team. Honestly, I see them struggling with the 107% rule.

So what is going to add Andretti to the grid, if not their experience in designing and building fast cars? Their experience in managing a racing team? Their Indycar team is in an absolute decline. An engine partnership? For the moment, all that Cadillac-GM promises is a rebadged PU, and the deadlines to enter as an engine manufacturer go by with no sign of their interest.

And what about the future? They have great ambitions about running the team completely from the USA. Which are no different than Haas' ambitions when they entered the sport. The fact is that the people with the relevant experience in designing and building an open-wheeler car (and that includes also Indycar's Dallara) are located in two very concrete areas of Europe: England and Northern Italy. So they only have two options: either recruit existing engineers or teach new ones. If they are going to recruit people, making them to move to another continent, they would need economic incentives, so an increased cost. And if they are going to teach them, it costs both time and money. Either way, an increased cost in engineering, with the cost-cap regulations, means a competitive disadvantage.

It is always good to remember that FIA's revenue depends solely on the entry fees that teams and drivers have to pay each season, so their interest is to have as many teams as possible, with the only requisite that they are solvent enough to actually show up to the races. On the other hand, FOM and the teams depend on F1 being a enjoyable sport so viewers want to watch and/or go to the races. I think that our interest as fans are naturally aligned with those of FOM and the teams.