Dungeon - Game Crash or Close

I have a question for all of you. I have noticed during the dungeon that if you close the game for many reason (haze, a bad decision, a bad luck ecc…) you can reset the room.
Is a cheat or is a feature ?

Because gems or gold is spent on the challenges most game developers allow stages to be replayed or resumed upon re-entry after a crash, even when the player causes the crash.

This is done to prevent support from being overburdened with tickets from players requesting remuneration for the gold or gems on such occurrences. This unfortunately occurred often in the early days of mobile gaming.

I assume this is why WoW functions this way.