When you dip that French fry in ketchup, who wants runny ketchup that just makes the fry all wet. This is why we need this tool.
A very important part of keeping customers coming back to your particular product is consistency. The last thing anybody wants is having the reputation of making some bottles of ketchup or applesauce different from others. This tends to make your customers think you don't care about them.
A lot of the different foods you eat contain a certain texture. Texture is certainly a part of the way we taste a food. If you get an ordinary bottle of ketchup or mustard you never even notice that it is sculpted to be just like the time you had it the last time. Tests are consistently run on batches of product to check the making of that item. If you got some mustard that was thick like molasses, you would probably avoid that brand again. It might be a small part of quality control, but it is important.