The iGPU performance doesn't really matter, it's simply that having an iGPU option on desktop has been the only missing part of AMD's strategy until now.
I'm sure the motherboard manufacturers are quivering in anticipation of once again being able to clog up motherboard IO panels with useless display outputs like VGA, so they don't have to put a decent amount of USB on them. Yes Biostar, i'm looking at you, kindly FECK OFF with 2000-era display connectors.
Honestly that's not a massive issue, considering that our very own lord and master W1zzard has demonstrated that 8 lanes are good enough:
https://www.techpowerup.com/review/nvidia-geforce-rtx-2080-ti-pci-express-scaling/7.html - I doubt that picture will change much with the next gen of GPUs.