Consumers are all about consistency. You can have a worse product as long as it is consistent every time. Ordering process being consistent is also important. That is partially why Starbucks pushes their terminology. The terminology also creates a feeling of being in a group and makes it more difficult to order at other places. Then add in gamified reward programs and a good phone app. Starbucks makes it difficult for local places to compete even with a better overall product.
I don’t know for sure but I assume of it is because light roofs require more maintenance to look as nice. Nothing shows up on a dark brown or black roof. A white or light grey would show dirt and debris. I don’t want to waste my time washing my roof because my HOA doesn’t like the way it looks.