It’s fast, not fancy. There are no dynamically calculated shadows cast by beautifully rendered translucent 3D dice here. The user interface is geared towards rapid rolling.
So, if you just surprised the brave party of adventurers with an army of thirty bandits who all need to attack, then this is the app for you. If the party wizard unleashes a spell that does 10d6 damage on your hapless ambush, then this is the app for him too.