: I actually would have rather the cinema scenes be in-engine, like they were
: in every other Halo games (well, except Halo 4's opening and closing
: cinematics). It would be more visually consistent plus it would be cheaper
: as well as take up less space on the disc. I honestly don't know why they
: thought CGI cinema scenes were a necessity.

1. Because they're awesome.
2. Because it's cool to see a new set of artists re-imagine the excellent original cutscenes that we all pretty much know by heart.
3. Because the in-engine versions aren't going anywhere. They're in the MCC and all over the internet.
4. Because the in-engine cutscenes in HCEA were lousy and if the same team is working on this, I don't trust them to do any better. Blur, on the other hand, has a sweet track record.