The argument is that learning assembly is useful, it gives some insights into what happens under the hood. That seems like a no brainer to me.

Would I use it for production iOS app, no, I don't hate myself that much.

Learning assembly is useful, yes. Learning assembly by reading an app written in assembly…not so much.

It's still very educational. It shows how ObjC method calls work under the hood, because even calling objc_msgSend() from plain C involves a certain amount of non-obvious magic (because of the variable argument list and return types).

And tbh I'm kinda surprised how little assembly code it is, less than most UI framework hello-worlds in high level languages ;)

You can just cast it to a function pointer of the right type and use it, the ABI is C-compatible