From what I understand, CryEngine is a nightmare to import models in and out of, among its myriad flaws and inadequacies. That applies to both the game version and the CGI versions, as the game engine is really just bolted onto the codebase.You think those fancy promo videos were made in-engine?
I do mean not in the Star Citizen engine. They may have used their StarLumberCryEngine to generate it, but i'm pretty certain it wasn't done by moving things around and animating them using the SC game engine. Everything will have been done as bespoke animations and scenes.
It might be easier for them though to drop the assets in Unity or Unreal though and make the videos there.
And no proof, but ask yourself, can the SC game engine do half the stuff they show in those videos?
You know CryEngine is bad when UBISoft had the rights to use it from the FarCry deal, and reworked it so thoroughly for FarCry 2 and onward that they actually renamed it completely.