What does force volume do?

Hi

I connected RoPieee via USB to PSAudio DirectStream. Volume control is via my preamp that is connected to PSAudio output.

Under the Roon tab, what does force volume control function as?
What happen when I disable/enable this?

Thanks. In this case, I should disable volume control both in Roon and RoPieee to ensure that volume control is done via the preamp.

Thanks @ged_hickman1