Punchline in the title,
really?
Skimming that post shows a lot of people saying that first layer doesn’t affect top layer. What is your definition of z height? We may have a definition issue on our hands here. To me, it means the distance between the nozzle and the bed on the first layer.
I’d be with you on the underextrusion though if the very top layer didn’t look so good. I would bet OP doesn’t have enough layers on top of the infill leading to an artifact that resembles underextrusion.
They’ve actually been trying to do this for years. There were actually a couple years of tests out in California I think. However, there are two big lobbies that always put a halt to it, tax preparation services (H&R Block, Intuit, etc.) and groups that want taxes to be a pain in the ass so we’ll all bitch about them.
Check out this episode of Planet Money if you want to learn more:
I’m not OP, but I would guess they cut out one dinosaur profile and wanted another to match. The copying guide allowed them to set the first cutout on top of another sheet of plywood and then trace around the template. You can see a sleeve around the router bit that would protect whatever the router is sitting on.