I really don’t understand the reasoning behind it either. How thin do we actually need our phones to be? It is also an expensive device to begin with, I wouldn’t plan to get it wet and would actively avoid doing so even with the IPX rating. Now you need to carry their adapter if you don’t have/want a wireless headset? Lastly, what if I want to charge and listen?
To me, the 3.5 wasn’t an issue that needed to be addressed and they are solving problems created by themselves.