Polished brass is very pretty but in all honesty, isn't really neccessary.
A good soak and wash in dish cleaning detergent, followed by a rinse in hot water is all that is normally needed.
Going whole hog, certainly won't hurt anything though.
The fact that the brass is shiney, won't make it any more accurate. But it is pleasing to the eye.
I have an acquaintance that likes to carry cartridges on a side saddle on his stock. He is fussy as hell about everything. Probably why he is so successful in his endeavors.
Anyway, he cleans and polishishes his brass fastidiously, trims it after every shot etc. His rifle shoots like a laser and it's a cheapy off the shelf, plastic stocked Remington.
The thing is, he uses "Black Magic" blueing on all of his cases. That way they don't gleam in bright light conditions. A bit overboard for me but that's just him.