I don't know all the science behind one system or the other but what I find on long rides clipless is that I dont have to think about foot position on the pedal.
I don't want to create a repetitive strain injury due to misalignment (having experienced bursa and tendon pain before) so with platforms I tend to look down to make sure my feet are tracking right. Not so with clipless. I assume cages would do the same thing.
On casual tours I am not as focused on high mileage so platforms work fine and allow a better suited walking shoe.