Correct re: another Pi – I am doing exactly that. USBridge Sig as endpoint, and a Pi with screen as display. Both running Ropieee, and pointed at my “Living Room” zone. Works well.
As an aside, the display Pi works with an OSMC remote, and also presents volume to control the output from the USB Sig (TMI but still cool: volume control is via an extension that @Boris_Schaedler kindly maintains for Rotel units – https://community.roonlabs.com/t/roon-extension-rotel-volume-source-control/46951).