Bose QuietComfort 35 Wireless Headphones II

I selected the Bose QuietComfort 35 Wireless Headphones II after extensive research and am very pleased with comfort, audio quality, and performance. A key aspect of my selection was the wired connection that I often need, as with in-flight entertainment systems. (I would have bought the Bose 30 earbud design but, amazingly, it lacks a wired connection). My only disappointment with the 35ii is that the audio jack is not the standard 3.5 mm (1/8 inch) style that we have known and loved for about 50 years. Instead, the phones have a 2.5 mm jack. I did not see this noted in any of the many reviews that I read—they all mention a standard audio connection. The phones come with a cable that plugs into the 2.5 mm jack and provides a standard 3.5 mm plug on the other end. But for the life of me I cannot even guess why a 3.5 mm wasn’t used on the phones themselves so that any standard cable could be used. So if wired connection is important to you be advised that you may wantto buy an additional (more robust and longer) adapter cable, and I do see some on Amazon. Apparently the smaller jack is used on other headphones as well. But why? Makes no sense to me.