Suppose you employed two people to wash your dishes, where the first
merely rinses, and the second does poor unreliable job of washing.
Does not sound like a good idea does it? Ineffective and wasteful.

Now, replace the second one with a machine. Is that any better?

Of course, to do this experiment you have to find some sort of machine
that washes dishes badly. How do find such a machine? Perhaps the
easiest way is to use a regular dishwasher but cause it to do a poor
job. You could, say, overload it or fail to follow the loading
instructions in the manual.

But wait. Is it not the case that tens of millions of people wash
their dishes in just this manner religously every day?