为什么官方AOSP网站阻止OEM从实现对AUD Accesory Mode USB C的支持到Aux适配器？ -- audio 领域 和 headphone-jack 领域 和 usb-c 领域 android 相关 的问题

I stumbled across some documentation from the AOSP project that encourages OEMs to only support digital to analog usb c to aux jack adapters which contain their own dac to convert the digital audio coming from the phone's usb c port to analog for the aux jack. What's so bad about supporting an analog only adapter that uses the phone's existing dac to convert the digital signal to analog and simply treat it's usb c port as if it were an analog headphone jack? Audio accessory mode at least on paper seems like a complete no brainer since it means the adapters are cheaper because they don't need to have their own dac.