[microcolonel]

JACK doesn't have Bluetooth support, nor array microphone support. It is also terrible on battery, and doesn't perform correctly on a non-realtime kernel.

That's not to say JACK isn't useful; but it isn't a solution to the desktop audio problem, it's a solution to the professional audio problem.

JACK also doesn't have the semantics and auto-configuration code which makes Pulseaudio work out of the box, and it is considerably more difficult to make JACK control clients. These are more reasons why even though JACK existed before Pulseaudio, it was not integrated with common user applications.