There are several third-party charger that got this working using multiple sets of overlapping charging coils. Only the ones correctly positioned under the device — wherever it’s placed — are activated. They work fine.Apple's device was meant to be an all-in-one charger where the user could place any device on the pad with little to no positioning thought ... 'set it and forget it'. All the third party chargers are 1. Usually created with one two specific devices in mind, and 2. Demand precise positioning of the device on the pad in order to ensure proper charging.
Two major differences are lack of Apple Watch support, only because Apple Watch doesn’t support Qi charging, and somewhat larger overall size. You can’t place two devices right up against each other and expect them to both charge; they need at least a small gap.