PCM2906C: Direct connection to ADC or DAC

Part Number: PCM2906C

Tool/software:

Hi,

Could you please clarify why the USB differential interfaces (D+ and D-) are necessary for data transmission to the chip?
Is it not possible to connect directly to the DAC or ADC inputs/outputs?
Does this relate to the signal integrity or even the voltage?

We want to send USB2.0 stereo input data to an Audio Codec like the PCM2906c with the DAC analog output (left and right) as the output.

Best regards