See this photo:

https://store.storeimages.cdn-apple.com/1/as-images.apple.co...

The camera bump on other models protrudes more towards the centre of the body. And thus the battery wouldn't fit (flush) and the Qi charging wouldn't engage properly.

So running the battery perpendicular to this photo isn't an option?

I'm sorry if I'm not completely familiar with this product: you are to have this battery attached at all times while you're charging, and it just stays in place? (gawd I sound like I'm from a different planet, I apologize -- wireless charging just never has been interesting to me)