It takes quite a bit to wrap your head around the SwiftUI way of doing things. I think a lot of people get frustrated and throw in the towel. I'm sure React is the same story.

And while you can't do everything in SwiftUI, it's pretty solid and capable now. I only have a couple things using AppKit in a large macOS project.

Why are they abandoning it? Could you please share reasons in as much detail as possible? Very interested to know.

It is fine for small toy apps (think the calculator), but it is missing a lot of functionality to build a full fledged app. Think collections, which is the backbone of most apps.

UIKit is very mature and has evolved to a really good UI platform. SwiftUI is not even close to unseat it. Maybe in few years it will mature as well, but for now UIKit is the way to go.

I only ever played around with making a toy app while following along with Stanford's Swift UI course[1], and even just the basic things I was doing there, I ran into multiple frustrating/confusing bugs.

As if it wasn't difficult enough to wrap your head around learning it in the first place, running into bugs makes it even harder because you think you're doing something wrong until you finally ask online and get told by people more knowledgeable than you, "I don't know why that's happening, wrap your view in a container and it'll work"

[1] https://youtube.com/playlist?list=PLpGHT1n4-mAsxuRxVPv7kj4-d...

At Beam[0] we are building a web browser that uses SwiftUI almost everywhere except for the text editor.

So far its been great to build UI and animations with. Each release gives SwiftUI more apis and features, so there are less and less older style apis to wrap in SwiftUI ourselves.

[0] https://hellobeam.com

Those scroll effects are quite janky on iOS btw