Is the third row in the Ertiga really usable, or just a gimmick?

As a 7 seater the Maruti Ertiga comes with a third row of seats which supposedly can seat 2 passengers. But the third row remains controversial, as to the practicality and comfort of it. But some users say it's only good for children or short trips and others argue it's more spacious than competitors in the same price range. In real world scenarios, how usable is the Ertiga's third row? Is it a real utility for large families or is it a marketing ploy? We will look into different user experiences and view points of the functionality of the Ertiga’s seating arrangement.