It's very typical for a visualist director, particularly Ridley dating all the way back to Alien and Blade Runner, to blow through many, many different concepts and designs en route to the final take.
I get why he went for the more humanoid Fifield versus other designs or the one we've glimpsed in other footage. I think the concern was that the audience would laugh at it or be taken out of the film by it. But while I was fine with the humanoid, I think the one we saw that's probably on the Blu would have been really wild.