Using 'supportedDestinations' with watchOS app doesn't generate an 'Embed Watch Content' build phase

I'm currently in the process of migrating my project specs from platform to supportedDestinations. According to the project spec, this should work for all target types:

Note that the definition of supported destinations can be applied to every type of bundle making everything more easy to manage (app targets, unit tests, UI tests etc).

I've noticed when I configure my watch app target with supportedDestinations, XcodeGen no longer generates an 'Embed Watch Content' build phase for the iOS app. Here is an example:

name: MyApp
options:
  bundleIdPrefix: com.example
targets:
  UniversalApp:
    dependencies:
      - target: WatchApp
    supportedDestinations: [iOS, macOS]
    type: application
    sources:
      - Universal
  WatchApp:
    supportedDestinations: [watchOS]
    type: application
    sources:
      - Watch

Is this a bug or intended behavior? Should I continue to use platform for my watchOS targets? Thank you!

Use the provided MyApp specification to reproduce the generated Xcode project, then inspect the UniversalApp target's build phases and compare it with the platform-based watchOS configuration. Done means determining whether supportedDestinations should generate the Embed Watch Content phase and documenting or correcting the observed behavior.