It could be just the novelty of such a view. I suspect that any interesting modification to your working environment leads to a short-term productivity boost, but these things don't necessarily persist in the long term. In any case, it seems like the VoI of exploring different working environments is high.
The under-utilized conference room with a great view has become the unofficial thinking room at work.
There is a whole list of little factors that contribute to the success of the thinking room, but major contributors include the both view, and the novelty.
If it's worth saying, but not worth its own post (even in Discussion), then it goes here.