Creating & improving that model is the competitive advantage. It's like saying what is the competitive advantage of compiled executables that run on customer devices. I estimate it's copywriteable.

But any would be copy-cat could simply push out the new model a day later.

I'm also struggling with whether such a model should fall under copyright. Models would naturally converge.

copyrightable?

I for one would definitely like to pirate such a model for use on desktop applications. This seems better than many existing local systems...

I think they still have the advantage of improving the base models ahead of anyone else. The fitting part I assume is tailoring an existing model to a specific user on device. They can improve the base model and have the competitive advantage by being first to market with ever improved model.