Affordability. I can't purchase and install my own solar system (to code level, inspected, CSA/UL approved) but I can buy and use approved installers for 4-8 times the cost of doing it myself.
I signed up to the GHG in order to find all this out, and it's far less expensive, even with the rebates, to just source and pay for it all myself.
Don't even get me started on heat pumps, that's another part of the scam. A heat pump is basically an air conditioner with an extra valve, but I was quoted almost $20,000 from an "approved" vendorto put in a pump of an "approved" make and model. I sourced the equivalent myself for $3000 and installed it in a weekend.