Why Bluetooth Ear Peice/ Mic Not an option for voice recording apps

[nocircuit]

Why is it that every audio or A/Video recording app that i have only defaults to the built in microphone when recording?
Most of the apps will play back on the ear piece but none use the bluetooth ear piece as the microphone, or offer it as an option.
Drives me nuts holding the phone up to my mouth as i'm walking thru a store and i want to record a note to self.
Ideally you could run a dictation/record app in sleep mode and tap the answer button on the bluetooth earpiece , hear a tone and talk into the bt earpiece and then tap answer button again to pause...
That way you can take audio notes as you walk around the store without even removing the phone from your pocket

 

[pinxue]

There are two kinds of bluetooth mic for iOS system, traditional single ear phone mic and a2dp headset. The first one can only used by system phone app, the later one can be used as usual audio source for recording.
As I use AirSlides often, it supports built-in mic, bluetooth mic and headset, but it is not a recorder app but a presentation tool.