Weight the increase in functionality relative to the "decrease" in usability. I think the additional functionality you get far outweighs any reduction in usability (which for the record I think is not that bad).
This. I still have all the buttons a non-idrive 3 series has has, and typically turn off the screen when I don't need the additional features. But it is really nice to have navigation, bmw assist, and all the additional features that come along with iDrive when I want them. I have a hard time understanding the downside.
You don't know what you're talking about. Usability is paramount. You would not be that found of idrive if it forced you through three menus to lower the windows.
Think about the cheap TV sets with no buttons. A ton of menus just to change the contrast.
Or microwave ovens unusable without manuals.
I have iDrive in my car.