When phones first started playing MP3s the manufacturers were very reluctant to put a 3.5mm jack in them (I'm not quite sure why...). I had phones which require

When phones first started playing MP3s the manufacturers were very reluctant to put a 3.5mm jack in them (I'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. Just think of how many times this will really annoy an iPhone user. In an older car? Aux cable doesn't fit. Lost your headphones? 90% of the replacements won't work (I'm sure eventually headphone manufacturers will catch up, but it'll take a while). At a party? Can't play music. 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.