In case you haven't noticed, bullets and such rush down the barrel being twisted by the rifling that cuts grooves and imparts the spin to stabilize it on it journey to wherever it was pointed when the trigger was pressed. This is by design. Something spinning it's way down the barrel on the end of a cleaning rod running across the rifling is not a basic design feature and not really all that productive since the bristles on the brush will not get into the base of the rifling grooves, where most of the fouling lays because the bristles are climbing up and the falling back into the groove missing the nasty stuff altogether, while wearing away at the sharp edges of the rifling that grips the bullet on it's journey down the barrel. If you don't think that a bronze or stainless brush can erode the rifling because they are made of a softer material than the barrel, think about the Grand Canyon. Water, which is about as soft as it gets dug that trench into the hard rock that comprises the canyon wall.
As for your comment that you have seen people using a brush on a drill to clean their rifle bore, it is very possible that you have observed this. I have been shooting competitively since 1975 or thereabouts, in both NRA and Military high power rifle competition and never in all these years have observed anyone at a match cleaning their rifle using the drill method. I doubt that anyone that is using this method to clean their rifles is anywhere near being a top contender.
As for a rifle barrel being expendable. I guess if you have a lot of money that you just want to waste it changing barrels that might be true. New barrels and their installation is not a cheap proposition. I have only replaced a few over my many years of shooting and none of them were cheap. A quality barrel goes anywhere from $250 for a cheap one to over $750 for a custom made barrel, and that does not include installation. That is a lot of ammo that could be sent down the barrel instead of never being purchased because the money was spent on an expendable new barrel You do things your way, and I will do them mine, however you can rest assured that I will never teach any of my shooting students your method. Good Luck