Shell, as in Gnome-Shell? No surprises there if so.

That said, at its core Pulseaudio depends on ALSA for the hardware handling.

Frankly the only useful thing Pulseaudio does it handle inputs and outputs when dealing with multiple sound devices. But then so does JACK.

Everything else, from volume control (hello hearing damage with default settings) to bit rate mangling, is massively superfluous.