Is it redundant to add umami to tomato-based sauces? On the wiki page for umami, it says that tomatoes are "rich" in umami components.

Does that mean it is redundant to add umami (such as monosodium glutamate) or soy based flavorings to tomato-based sauces, or is there a benefit?

For example, a typical tomato-based sauce is cocktail sauce, which often has worcestershire sauce in it as an ingredient. However, the main active component of worcestershire sauce is fermented fish sauce or soy, which is primarily valued for its umami. So, if umami is already present in the tomatoes, why add the worcestershire at all?
The Wikipedia article you link actually hints at an answer. It points out that there's a synergistic effect when combining different classes of umami-rich foods, leading to a greater flavour enhancement than would be expected simply by adding the effects of the ingredients 


  Japanese make dashi with kombu seaweed and dried bonito flakes;... and Italians combine Parmesan cheese on tomato sauce with mushrooms.


So it's certainly traditional. But in your example the tomatoes bring some sweetness along with the umami, while the Worcester sauce (like soy sauce) is salty and so rich in umami it's used in small quantities. The effect of combining them is a more savoury sauce than one that tried to get all its umami from tomatoes. Red pesto uses parmesan to similar effect.