While I have never had the situation of a dealer reading out the board, in my rooms, the dealer always reads out a card that is flashed. Which, when you think about it, puts a lie to the "visual game" argument the second any dealer does this.
Really has nothing to do with the situation at hand. I would imagine the reason they do this is because once the card is flashed or exposed, it's a lock that they're going to get asked 2 or 3x "what card was that?" anyway no matter how long they leave it face up for everyone to see. Might as well verbalize it ahead of time.