Nothing wrong with that - chances are you'll use it at one point or another. Most cars and stereo systems still use 3.5mm. Even for people who have Bluetooth in their cars they often prefer the stereo cable as it gives better quality, has no weird pairing issues and doesn't drain their battery.
I've ran both wireless and wired headphones and have settled on wired. It's just better, better audio quality, better headphones for a lower price, no waiting for the headphones to initialize, no forgetting to turn them off and finding your battery half dead, no having to charge them every few days. Just plug it in and go.
Hopefully this move will put pressure on manufacturers to get costs down on these wireless headphones and get the more off-brand audio manufacturers who often make the best products (quality/dollar wise) interested.