I'm a little confused about why you need Unity to launch a web view in full screen. It's been a minute since I've written an Android app, but isn't this like... less than a hundred lines of Java?
They mentioned also shipping on iOS so they are probably leaning heavily on unity for cross platform functionality.
Surely the Swift code can't be much more?
Not "they". He. I'm only person. And yes, I use Unity because it's cross platform. Well, at least it was cross platform, until they closed my Google Play Developer account 2 days ago :-(
It was a stupid experiment. A useless app I shoud have unpublished years ago. I used Unity because I'm familiar with Unity and didn't want to deal with Android Studio and native development stuff.