They are pricing the Quints (Gold and Silver) based off "Proof" coins (which don't hold their numismatic value in the free market) but if you request delivery, they deliver a "Bullion" version. So they are not priced off of what will be delivered.

And you have to pay Federal capital gains taxes in the USA on Gold and Silver bullion gains just like any other commodity. They same will be true for the "Quint" if anyone is foolish enough to buy into it and make a gain and then report it.