Thank you for stating the obvious. We all know this, that's the exact point of a GDKP run. This isn't adding anything to the thread.
I learned about the concept of GDKP from this thread, and find it very intruiging.
I'm a little surprised noone has brought up the issue of loot drop and -win volatility, and how GDKP runs help lessen this. In a normal run, it's hit-or-miss the jackpot: you either walk away with nothing, or, if you're the lottery winner that week, that BiS/mark for free. By doing GDKP runs, you're in effect insuring, and thus ensuring, your cut of the pot: either you get a bunch of gold, or you'll get the item you are seeking at a cost.
All else being equal, GDKP runs lessen the luck factor regarding a player's chance to win the drop. After a few GDKP runs, assuming the raiders are equals, a player will have the gold needed to ensure he/she "wins" the drop. In normal runs, luck plays a much bigger part, and bad streaks can continue for a long time.
Speaking as a pro poker player who's learned to both protect his bankroll and ensure a steady income (even at the cost of Expected Value), I find this very appealing.
I'm going to try to introduce GDKP to Argent Dawn (EU) Alliance side very soon, where I don't believe there has been any yet. Wish me luck =)