Given the durability of panels, it'd be fascinating to see roof redesigns, and some changes in panel packaging, that standard large rectangles become the basic components of a 30 year roof. Or as siding. I've seen them used vertically on the Southern walls of commercial buildings in Alaska, and they looked great.
Absolutely. Energy has to be baked into every structural element. Either producing energy, or storing energy, or providing insulation, or acting as a transfer medium (heat pump).