With my understanding 6DOF robot arms are used when you need to be flexible. Today you do this tomorrow (or in a couple of months) you will need to do something

With my understanding 6DOF robot arms are used when you need to be flexible. Today you do this tomorrow (or in a couple of months) you will need to do something else. The more diverse set of things to do the better. But if you need to do the almost exact same thing many times over for a long time it is better to design a production line that doesn't use 6DOF robot arms at all.