Makes sense. There's plenty of freely available code and data online for using web tech. Any number of free online bootcamps spawned in the mid 2010s are full of "Become a React developer in 6 months" type of content.
Native, especially on Windows and macOS, have been the domain of proprietary apps there's not much code outside of tutorials online to train a model on outside of official documentation.
I made a couple of small menu bar utilities for mac using Gemini, and it was OK at best. Kept wanting to use deprecated APIs, but with a lot of handholding I got them to work.
Would be neat to see Apple put out their own model specifically for Swift/SwiftUI