Think of the characters as sort of Animal Crossing villagers. They give you information about how the game works, but sometimes they talk to each other, and some just pop up to say "Hey, nice car!" before telling you how much they love it.
In the brand-central, you'll see the history of all these car manufacturers. But, there's a second timeline of world events, like the titanic sinking or... the Panama Papers being leaked.
It makes the world of cars feel relevant to our lives, and feel like a real culture full of quirky and passionate people!