Using the sausage tubes on the grinder is only good for getting grind into the plastic burger/sausage freezer bags. 
Until I bought a stuffer, I used my grinder tubes for many years to make snack sticks, bratwursts, link sausages, etc. It took a little more effort, but I got it done, and no one had any complaints. I will say, a stuffer is worth every penny though!