It made sense for onshore wells where after a discovery it took a very short amount of time to lay gravel on a production site, install a tank and separator and begin production. For an onshore rig capable of drilling to 16,000' MD the day rate was on the order of $8,000 - $10,000/day (this was in 1977-1979).
In the case of offshore in ultra deep water, assuming a discovery in 2017 it is unlikely there will be first oil before 2022-2023. I am not sure Pacific Drilling wants to wait that long to be paid from their assigned interest, even if they have the assurance of follow-on wells to be paid for. They need cash now.