I'm very curious how this will be handled by OEM's.
Water resistance is pretty much universal at this point, and as far as I know that's dependent on an airtight seal being maintained throughout the device.
The EU rule forbids use of tools, chemicals or heat to remove the battery. So how does Apple, Google etc retain the IP68 rating if the back is removable via screws?
I obviously think this is a really great step for mobile phones; I miss being able to carry a second battery for long trips back in the day. But I'm concerned that this will also make phones bulkier, heavier and less water resistant.