If you can’t know if it’s right or wrong, and have to double check it, why use it in the first place?
Me and my partner alternate doing the cooking. She doesn't know if I'm going to make a mistake and serve her something she doesn't like (it has happened). Does that mean she's better off doing all the cooking herself?
"If it's not perfect, it's useless" is a fallacy. So the question is, how good does it have to be to be useful? That depends on the task, and especially on the cost (however you measure it - dollars or hours or whatever) of verifying whether the result is good compare to the cost of a person doing the task.