Most car manufacturers seem to use ALL CAPS for the interiors's buttons and switches, at least when they are not using symbols. Example:
They even use capitals for things that are not even controls, like the indication where the AIRBAGs are in the car.
I thought that all caps where harder to read? (http://uxmovement.com/content/all-caps-hard-for-users-to-read/), so I am wondering: is there any specific reason for this?