The "Invisible" Labor Savings: A builder usually pays for a framing crew, then an electrician, then a plumber, then a drywaller. With your system, the wall assembly is the electrical and plumbing rough-in. You are effectively cutting three separate labor cycles into one.
The Wall Map (The "Lego" Effect): By providing a "Wall Map" for every project, you reduce the need for highly paid site supers. If the panels are numbered and the functions (plumbing/electrical) are pre-specified, the room for human error drops to near zero.
The Maintenance Advantage: The mention of Access Doors is huge for commercial or high-end residential clients. The ability to inspect or repair "inside the wall" without a sledgehammer is a massive selling point for long-term property management.