World corrupted / deleted after a power cut or game crash

I was playing Minecraft bedrock edition with my sister when suddenly a blackout occurred. When power came back, I launched minecraft and then saw my high effort world got corrupted, why would that happen? What's the purpose of auto save if it doesn't help in emergencies? Worlds also corrupt when the game crashes, then why is auto save there if it doesn't help?  If the game crashes or the console got turned off suddenly, I should spawn on the latest spot the game auto saved, or else then auto saving have no purpose. Ease help, minecraft isn't playable for me at the moment because power isn't stable in my house, I'll have to wait until you guys fix it in order to play.