I think it is basically a way to gain position (to some degree) in the hand. You now get to act last/second heads up. That's not exactly what happens, because the person in late position is still acting last before the next card comes out.
Sometimes you see people do it when they have a hand that the flop will very clearly define, like a small pair (they spike the set or not).
There are lots of reasons NOT to do this-- you may want to bet the flop for any number of reasons. David Williams, the year he got 2nd in the Main Event) was checking in the dark for no reason, just to look cool in front of his hero Marcel Luske, but made the mistake of giving a free card to hurt himself.