So the significance here is that if you had remote access to a single wind turbine, you can control the others? Implying, if there were a vulnerability in the control system of one turbine, the rest of them are exposed? Rather than showing that you can stop wind turbines from spinning, if you had physical access to the turbines.

Their "hack", which requires physical access, is about as practical as throwing a physical spanner in the mechanics.

EDIT: I'd like to point out, there are reasons why you might want to be able to access the SCADA system of other wind turbines, from the network access of one wind turbine, which would be to allow wind-yaw optimising wind lidar systems to optimise the yaw of other, local, turbines.