[ArturiusX]

Well, let me put it this way. The reason for betting out is to protect, right?

Wait for the blank on the turn. No blank (a spade) and some action, its an easy fold. But if it is a blank, we can lead out and push out those single spades who fear a slowplayed made flush/higher flush.

But if we bet this flop, single spades will call anyway, and will probably call a turn bet too.