People say it looks wrong, because they are used to seeing them.
I dont have the fake vents, just the moulded bonnet.
If I had them, I would want them to be real, as "fake" makes it look like a Halfords boy racer car, covered in "fake" carbon fibre, that actualy does nothing other than adding weight.
However, there is more to a vent than just cutting a hole in the bonnet. As mentioned above, there could be an insulation issue. They could let water onto something that does not want it. They could change the airflow within the engine bay and cause heat build up problems elsewhere. In an ideal world, they would help with cooling and underbonnet temps, but are they generally a problem with a forfour?
Each to there own. It would be a boring world if we all had the same, or even all wanted the same. There is no "right or wrong"