When phones first started playing MP3s the manufacturers were very reluctant to put a 3.5mm jack in them (I&#x27;m not quite sure why...). I had phones which required custom adapters, either for proprietary ports or for 2.5mm jacks. They were a complete pain to use, really easy to forget at home, and as a result I never really listened to music using my phone.<p>Just think of how many times this will really annoy an iPhone user. In an older car? Aux cable doesn&#x27;t fit. Lost your headphones? 90% of the replacements won&#x27;t work (I&#x27;m sure eventually headphone manufacturers will catch up, but it&#x27;ll take a while). At a party? Can&#x27;t play music.<p>In my experience, trying to get Bluetooth or other wireless streaming systems working at a party when 10 different people want to play music is a nightmare. The aux cable is a solid reliable backup.