From the cargo perspective, you have to look at the alternative (Dover/Folkstone), which for a freight operator using lorries, constantly being stacked on the M20, it's a credible alternative.
Instead of having lorries stuck for hours/days on end, fly in/out of Manston and transfer goods on to lorries from there?
Would very much depend on the overall cost, but the time save could more than make up for it, especially with Brexit/ Enhanced border checks coming in soon...