A Google spokesperson explains:
Promoted pins in navigation are not new – they let people see relevant ads for businesses like gas stations, restaurants, and stores along their route. To avoid driver distraction, these ads do not pop up, expand only if they’re tapped on, and disappear quickly after a short time.
Interesting! Do they support Android Auto?
They both do. I have never used that function, so I cannot say how good the Android Auto integration is.