Is it better doing something useless or doing nothing? Doing nothing, absolutely! Counter-intuitive? Find out more now!
If you are doing something useless, you are wasting resources. Somebody (the boss? the quality department?) might think it is critical work because “things have always been done this way”. It is possible that you do that useless stuff wrong (oh no!), therefore afecting parts of the process that are really important. Maybe one day will come when you need that time and resources to do something really productive, but everybody will be very busy doing the wrong thing, and the value-added work will wait forever.
So please, if there is nothing to do, do nothing. It is way more productive.