BMW outsources many of its parts.
The top-of-the-line seats, they outsourced to Recaro, which has a reputation for high-quality seats even outside of BMW culture.
Generally the most durable and considered the most elegant, even if not the most practical
Black is generally considered the most classy color for an interior, even though it tends to be less practical.
Black paint visually blends with the black trim, to make for a shadowy type of look that emphasizes the pretty shape of the car.