It's a sheltered publicly accessible space in an urban environment.
Station is being built using cut-and-cover so the entire length of the station (platform and headhouse) will be excavated anyways, not sure if that makes a differernce.
For the New York subway comparison, it has smaller footprint. Notice how the elevator is in its own structure at the back. Whether it's a better setup is a matter of opinion.
NYC: smaller footprint, station is open to the elements
OL: larger footprint, station is sheltered
As I have noted in my previous post, a structure having escalators, elevator and waiting/gathering space under the roof, it is not large. Think of how this NYC subway entrance would look if the space between the escalator/stairs and elevator are covered up.
commons.wikimedia.org