My only issue with digital dice is that the more realistic applications potentially allow you to cheat. There are too many variables that could be customized by the user, of which the opponent is unaware of: dice weight, size; rolling surface type, resistance, area; air pressure and density, etc. Ultimately, there is no way to verify whether the application is favoring the player using it without having a duplicate device on hand.

A simple app that generates a random seed and simply displays two numbers is a safer bet, but I prefer real dice.