I don't think anyone uses white to border their court and I suspect it is because it would look filthy in no time.
When I first got season tickets I got to go down on the "Valley" court, it was pretty surprising to see how beat up the court was, and it had only been really used by the players at that point, the fans were barely being let back in the building. The only team I can think of that uses a lot of white is the Brooklyn Nets and they have, by far, the ugliest court in the league. The contrast makes the players look dead for some reason.
Also, as I have said, I think the darkness of the arena and the border of the court will make the court pop, especially in person.
Yep I was going to say that is why the outside is black. During a game that outside gets so much foot traffic it will keep it nicer on TV