Isn't this really just to pique the interest of casual gamers that have only sorta-kinda followed the story of Chief?
I could imagine people who only play the campaigns once or twice (and never followed the novels, comics, Hunt The Truth, etc...) being curious about Halo 5 (hell, this may be the first time those ultra casuals even heard that Halo 5 is coming out soon) after randomly seeing this on TV.
That being said, as a Halo fan, this was disappointing. But I feel as if this was aimed at the broader audience, not us.
And this...
...makes it more interesting.
There are those of us who have hunted the truth and know that this is just bullshit ONI PR and then there are the masses that have no clue what's really going on behind the scenes. Kinda breaking the fourth wall in a way? IDK....
But, disappointing for me. Let's hope something 343 releases can beat that live action ODST trailer (still the best).