You may still do something about this if it's your own watch app. The Xcode 7 Beta 5 Release Notes explain:
watchOSWatch apps written with Swift code may not install to the Watch from the phone.
- Workaround: Add STRIP_BITCODE_FROM_COPIED_FILES=NO as a user-defined build setting on the iOS, watch, and extension targets (or just add it as a project default).
I.e. select the "PROJECT" entry to get the setting as default everywhere in the project build settings, then press the + next to "All | Combined Levels" to add the setting with value above to the list at the bottom of the screen.
Max.