flabbydan,
If there is any wear on the seating die, I'm sure it's negligible. After all, you load very few and the seating die isn't nearly as tight around the bullet as even the brass is. I can assure you it's worth doing with most any factory barrel through which you shoot cast bullets. It eliminates the rough spots in your barrels thus giving fewer places for brass and/or lead to "catch". It's helped every barrel I've done it to. Just my experience. I'm sure others will take exception.