I have avoided enabling the volume control, because I use a pre-amp with a a DAC, (currently fed by an HDMI - SPDIF converter), and the software option warns of degrading the sound quality.
I have had a couple of thoughts. If the volume control is disabled, could it be removed from the interface?
If someone has a 24 bit DAC and is playing 16 bit sources, a simple stepped volume control with no degradation can be achieved by outputting at 24 bits and shifting the bits in the samples down by up to 8 bits (and padding with zeros). (Obviously when applied to 24 bit sources, there will be a progressive degradation down to 16 bit quality.) Such a system should really displayed in dB rather than percent.
Could I request these features, please?