Nothing baffling if you look at it this way:

Within Chrome it's Chrome vs Android (and possibly a few other teams). To quote https://www.quirksmode.org/blog/archives/2021/08/breaking_th...

--- start quote ---

When performing Valley Kremlinology, it is useful to see Google policies as stemming from a conflict between internal pro-web and anti-web factions. We web developers mainly deal with the pro-web faction, the Chrome devrel and browser teams. On the other hand, the Android team is squarely in the anti-web camp.

When seen in this light the pro-web camp’s insistence on copying everything appy makes excellent sense: if they didn’t Chrome would lag behind apps and the Android anti-web camp would gain too much power. While I prefer the pro-web over the anti-web camp, I would even more prefer the web not to be a pawn in an internal Google power struggle. But it has come to that, no doubt about it.

--- end quote ---

A flutter web app is also a PWA. There’s nothing DOM specific about a PWA.

Think of it this way:

If you are a small business / entrepreneur and you have a working product on one platform, you should be able to port to another platform with minimal effort, where you can at least have a MVP without having to recreate your front-end from scratch.

- If you already have a website and you want to do an app, PWA is probably a simpler path compared to recreating your front-end in Flutter.

- Likewise if you already have a working Flutter mobile app and your users start to ask for a web or desktop version, it's easy to get some sub-optimal version out with less effort if you can re-use a lot of your Flutter code.

It also makes it easier to maintain if you structure your code in a way that separates out the logic that's specific to platforms.

If you manage to achieve product-market fit and your business benefits from your users being first-class citizens on the web and on the phone, you can start to invest in those development teams.

Companies that size generally don't follow one set of perfectly aligned goals. Both make sense for Google to support, even if they occasionally contradict each other. And that's before you look inside who exactly benefits from which goal.

You forgot Kotlin/Native with Jetpack Composer.

That is what happens when each business unit has their own agenda.