I'll speculate on why Harrah's banned live Harrah's chips from the show. In LV, several casinos have gotten their hands slapped by Gaming for selling chips or tokens above face value in the gift shop. Gaming wants all chips exchanged for face value only. And in Colorado, certain Colo. chapter members gave one casino a hard time for selling LE sets above face in their gift shops.
Even though the borse floor is not the same as a gift shop owned/controlled by the casino, I think Harrah's just wanted to be sure there wouldn't be any complaints to Miss. Gaming Control about live Harrah's chips sold for over-face on their premises.