Salt has an unusual effect on fat, as well. When you eat sweet butter on bread in your mouth you feel some kind of fat, some kind of oiliness on the palate. If you do that with salted butter you don't get that same sensation.
Salt has several functions in baked goods:
Without salt, bread rises faster and air pockets enlarge where the gluten has broken, allowing holes to form. Bread made without salt will taste bland. If you choose to eliminate salt, decrease the proofing time so that the large air pockets don't have time to develop. Salt should not be eliminated from recipes using automatic bread-making machines.