Dunking a crusty piece of bread into soup certainly makes the meal even better, but adding the bread inside as it simmers yields a more velvety product. Given its propensity to disintegrate when cooked in broth, bread is the perfect addition to make soup more filling - this is particularly true of rye bread. The baked good is earthy and thick, adding flavorful and textural depth to soup.
There's a very big difference between a good pastrami sandwich and a great one, and much of that comes down to the meat. You know right away when you're eating a perfectly cooked piece of pastrami - it should be tender, juicy, and bursting with so much natural flavor that you shouldn't need any toppings to compliment it. But there is one other small step you need to take to build the ultimate deli-style pastrami sandwich, and that's toasting the bread.