there is literally 0 difficulty increase between saving and not saving.
the only thing that this would do is inconvenience and upset people, for no reason as none of the actual gameplay itself changes.
app crashes? get a call? need to be a human and help your family? literally anything? theres a multi hour run down the drain. all of what AdobeOneKenobi said.
not to mention this doesnt in any way encourage new players to finish a run-- runs arent quit (and neither is the game) because people arent held at gunpoint to finish them--- theyre quit because people move on or lose interest. this is not a kind or responsible method of keeping players invested.
instead you should focus on positive gameplay feedback loop type suggestions to increase new player investment.