Cooking with dates as a sugar replacement definitely changes the sweetness profile of any baked good.  A brownie using date sugar or date paste is almost certain to be less sweet than a traditional brownie.  Not that the less sweet flavor is a bad thing, I actually prefer it but it may not be to everyone’s taste.   Dates also add more moisture to the vegan date brownies so it required adjustments to the other liquids added to the brownies.  Baking with dates adds a caramel flavor and color to baked goods which works perfectly for healthy vegan brownies, but may not work for every single baked good recipe.