Just checked IA app and they have 2 simple features that made me super mad that d2e doesn't have:
-save&exit
-restart current mission
Tbh exit without saving should be there too but this can be done by killing the app process.
At current stage in d2e if you defeat a boss by misclicking or not understanding his ability or something and end turn then your whole campaign is ruined. Unless I'm missin something