Marco Arment:

Rewriting “Send to Watch” playback to use the only supported alternative would likely take at least another month of development and testing that I currently can’t spare, and due to its limitations, the resulting usability and experience wouldn’t be good enough for me to confidently ship.

Therefore, I’ve decided to remove “Send to Watch” in the latest update today, a bit ahead of watchOS 4’s expected release, before anyone else gets accustomed to it.

I was really excited about this feature when it shipped in April, but in reality, I never actually used it beyond my initial testing. The truth is, I’m never without my iPhone and having to transfer episodes is more trouble than it was worth.