Why would you prefer something worse in every way? (And don't say battery life, the dGPU models also have an iGPU for that.)
Seriously, the iGPU fanboys need to get a grip. They seem to prefer something that is objectively worse, just because, and are completely ignorant of pretty much anything technical regarding GPUs (integrated or otherwise).
"Given the option between getting $100 and $80 I'll always prefer $80 option" makes about as much logical sense as your statement. There is NO downside to having the dGPU (since you also get an iGPU for good battery life included).
The only reason for picking an iGPU is price and thermals.