The problem with the ~ 4:3 ratio this will have unfolded is that most people like bigger screens for watching videos. They'd probably be better off having it be basically a square when folded which is fine for using it as a phone or texting someone.
I've always said though that for a folding phone to really take off it'll need to be a trifold device to get the ratios right. That will mean something a LOT thinner. This thing would be REALLY thick when folded, though they might not have showed the real device that goes on sale. If this is what goes on sale, it isn't going to sell much.