I believe this pretty much confirms the lack of BT headset support, of course given that the rumor about the app is correct.
We know that none of the official nintendo controllers offer headphone jacks, which means that in docked mode there only are three options for voice input: directly through Switch's headphone jack, BT wireless headphone, or the "app" we all love so much.
I am going to leave the dock on my desk since I'll be using my PC monitor, but the first option is not so viable to the majority of TV audiences. The second is perhaps the most preferable with its easy set up, but the rumor is leading us to the third option where we can only talk through the smartphone app. I don't believe it is that hard to put a chat into the system, so there must be a reason why Nintendo is eliminating the second option, and given Nintendo's history I'll say the Switch will not offer BT headset option, at least for now.
Discussion started at here by switchhype