Why would it increase the value of the other coins in circulation ?
I'm no economist, so correct me if I'm wrong, but here's my understanding:The Bitcoin economy has a certain market cap. The market cap divided by the number of coins is the price of a coin. Get rid of a large number of coins, the price per coin goes up. This could also have the effect of lowering the market cap, but there would still be a net gain per coin.
Tightening the supply generally has the effect of raising the value of the product (law of supply and demand). But I'm not sure it would have much impact in this case because Satoshi has never used his bitcoin stash. In effect they've been outside the money supply anyway, as a result. Or to put it another way, money supply is a function of the total quantity of money (bitcoins), and the velocity of the money - that is, how fast it is transferred from one party to another. Money sitting in a stash has a velocity of zero, and thus no impact on valuations.
(I'm not an economist either, though I can think of at least one Nobel prize-winning economist against whom I think I have a better handle of the subject.)
