Why is London City getting a virtual tower? (Source)

London City is not a remote-low-traffic airport. Staffing a remote airport is like having lighthouse keepers. That I understand.

And yet the tower will be closed, and moved off-airport to become a virtual tower.

All those working on the project are very happy apparently, and the press releases (and videos) don't reveal much. I don't get it. The only thing that I saw as a positive, was an augmented reality overlay on the screens that highlights nearby drones.


  (...) a critical new safety feature means the cameras will be able to pick out rogue drones near the airport, as well as light the runway at night.


Why would a major airport undergo such change? What problems are being solved?
London City is severely space-constrained, being on an island in the Thames. Moving the tower means more space for functions that cannot be moved.


  ... will also include an extended terminal building, enabling it to serve two million more passengers a year by 2025.


A high tower means substantial foundations, so you can't just stick the tower on top of another building. You have to build around it.