Niantic is ending support for the Apple Watch after July 1st beyond that, you can’t connect your watch to the creature-catching game. Simply put, it’s not as useful any more. Now that Adventure Sync can track steps, earn Buddy Candy and hatch Pokémon on your phone, Niantic wants to “focus” on using the feature on one device instead of splitting your attention.
Your smartwatch stil won’t be wasted on the game. Adventure Sync tracks data through fitness apps, and that includes data sent from the Apple Watch. Your gym routine will help you make progress, then. It just won’t help as directly as it did before. In that regard, this isn’t so much a withdrawal from the Apple Watch ecosystem as it is a more intelligent use of the device on your wrist.