Even simple tasks eventually are done wrong. Your star engineer will have a bad day, he’ll forget to deploy to one of your servers and it’ll be a big problem. An error in certain industries is ok. Your burger didn’t have enough ketchup, or the bun was crushed. Most people won’t care. An error in engineering is costly, people and dogs can die. Software is no exception. In software this mostly manifests into revenue loss, customer trust loss, and not to mention the time and inconvenience to engineers. Nobody wants to be the person that has to fix it really quick at 2am.