Could someone please explain in what situation do you use a BlueTooth messaging app? Like, even BT5 range won't exceed 400 meters. What good is this? You're not going to send images to journalists from protests with it (you'd do wisely to keep it in airplane mode until you get home and then you'd upload them to their securedrop or whatever), and you don't need off-band security to let the kids know it's dinner time.
Now that Wi-Fi Aware is supported on iOS, I think supporting it should significantly expand the transmission range.