Because Apple does everything carefully and lays the ground for change.
Apple smartwatches, among other things, do not support third-party watch faces. Apple offers a lot of native options, but still the choice would be much wider if third-party developments were supported. And Apple explained why it does not implement such support.
The company explained why its smartwatch does not support third-party watch faces
It turned out that it was all about careful study and planning. First, Apple goes to “great effort” to ensure that all watch faces work “uniformly and simply.”
Secondly, Apple has to think in advance of the aspects associated with possible changes to its own watch faces. That is, if the company wants to change or add something, the watch faces should allow it to be implemented.
