It's a cool stunt, but nothing more. The days of using assembly language in everyday business applications are long gone. Questions of portability immediately come to mind, as well as productivity losses relative to other companies/developers who are producing code faster and more efficiently.
Well, never estimate the power of "hobby". When announcing Linux 27 years ago, Torvalds said "just a hobby, won't be big and professional like gnu". Now name any device and probably someone has ported Linux to it.
In a similar way, probably old-school asm programmers will gather to write mobile app framework in assembly. You know, HTML/JS/Java/Swift is for sissies.
True, if you're writing a typical app, it will probably be easiest for you if you write it in the same manner as most other people.
But if you are doing something very new or unusual, a sample project like this can be invaluable, since it shows the exact set of system calls needed for an app and roughly the minimal code. This is useful if, for example, you're trying to make a new language framework run on iOS (like Swift, Kotlin, or Rust), or if you're trying to answer questions like, "How much of an app's size is unavoidable?"
