Unless you were concerned about the safety of someone having to look at a screen to operate vehicle controls. Otherwise you could just make it a smartphone app and ditch the screen entirely.
Not every cars are made for Japanese, far from it, but abolition of LCD based map-radio on a standardized slot is a weird hill to die on, so every cars has it anyway.
And, I think, this is where the actual "it's cheaper to..." argument begins: since every cars will have the standard issue map-radio, it _can be cheaper to move buttons into it_. Differences between the standard version and one with this context is whether the cost of the entire 2DIN screen is included in it or not - if the screen cannot be removed, to shut up whining Japanese or not, it becomes sunk cost and becomes a constant term of equation, which physical buttons have no chance of winning.
It would be hard to justify not using a screen these days, IMO.