It Will ‘Just Work’
At its most basic level, Apple’s wireless charger would be designed to work flawlessly with all of its products that support wireless charging.
For the most part, wireless charging hasn’t been a big problem for the iPhone—as long as you’re using a Qi-certified charger. However, charging AirPods is much more hit-and-miss, and there are very few Qi wireless chargers that can handle the Apple Watch without making special accommodations for the smaller device.
If Apple were to release its own charging mat, it would be reasonably expected that it should be able to charge ALL of these devices, one hundred percent reliably.