Replaceable batteries are one thing, but truly hot swappable batteries like you're asking for will absolutely effect the waterproofing and add a lot of weight/size. Is there a reason you can't just bring a battery pack in your rucksack? They make magnetic ones you can slap on the back and be on your way.
Continuing to take photos with a battery pack hanging off a device is no where near as simple as popping in a fresh 100% battery and coninuing as normal.
just to note, wireless charging is very inefficient. From the page you linked:
"Due to a 30% to 45% energy loss in battery cells and conversion circuitry, a fully charged 5,000 mAh power bank typically offers an estimated 2,750 to 3,500mAh to power devices"