The price rose so fast because of speculative investment and trading, fueled by predictions that it would one day replace VISA. That surely is a use for bitcoin that he did not expect. If there is something that the world did not need in 2009, and will never need, is another penny stock. He would not have bothered creating bitcoin, if he knew that it would turn into that.
If he did not expect that to be part of the behavior, then he was completely stupid about markets, and I rather doubt that.
Once the possibility that it can someday replace VISA exists (or alternately function alongside VISA at a similar scale), people will speculatively trade on that possibility.
What I meant is
other people started talking of bitcoin taking a significant slice of VISA's market, either sincerely or to pump the price. Satoshi himself does not seem to have intended that, and even suggested the opposite:
Commerce on the Internet has come to rely almost exclusively on financial institutions serving as trusted third parties to process electronic payments. While the system works well enough for most transactions
I read that as "bitcoin is not meant to replace VISA or bank wires, but is meant to be used when a third party is not available or really not appropriate".
Anyway, block rewards will not necessarily increase nor decrease in USD value, it just depends on future market conditions. Either is possible.
Of course. I was trying to guess what Satoshi was thinking when he defined the halving schedule.