More importantly, the points are caped and when Cataclysm actually releases, the "hard cap" gets enforced, meaning anything over the cap gets converted to money. Think of it like honor. If you're capped at 75,000 honor, and it costs you 70,000 honor to buy a piece of gear... how many pieces can you buy? The new cap will be 4000. If you have 500,000 justice points that were converted in the first pass, you had way too much to begin with. However once the hard cap is enforced, you drop to 4000 instantly, and any surplus is simply lost (converted to money). Now if an item costs 3750 points of 4000, how many items do you think you can buy with all that left over currency you had from Wrath of the Lich King?
Even if you can have access to the new gear with the points, similar to how honor has always worked in the past, you are still bound by the hard cap on the currency and that limits how much "pre-farming" you can do.
"In anything, if you want to go from just a beginner to a pro, you need a montage." /w TankSpot WTB Montage for Raiders.