Indeed. However, the Latin language has no 'power' in and of itself, rather, it is gramatically more precise than English. That Latin is no longer a secular language means that its vocabulary and grammar does not change. Therefore, what was written 1000yrs ago would mean the same thing today as it did then; 1000yrs hence, it would mean the same. Herein lies the beauty and usefulness of the Latin language, hence Latin being the offical language of Holy Mother Church.
Yes, it is supposed to be Latin, but it is permitted to be done in English. Because it is done in English, this video allows the viewer to see/hear/witness the powerful significance of the prayers. Exorcists only use Latin because only Latin is succesful against the devil. This is why it is preferable to use the powerful Latin language in conjunction with the powerful age-old prayers!