Why "Pre-oiled Pita"?
It is really common to brush a pita with some oil prior to heating for an extra crispy treat. We sort of do that at my house, except be coat the heating device (a frying pan) with oil instead of the pita itself.
From kontos.com:

Pre-oiled Greatness
Our pre-oiled breads are infused with extra virgin olive oil for flexibility and rich taste.

So pre-oiled pitas have more flexibility, so to be more convenient for wraps, and pre-oiled pitas have a richer flavor and crisp better when heated.