All "smart" devices could potentially be used to disrupt the grid. Consider a "smart" heater or kettle, or any other appliance that has the ability to draw significant current. All you would have to do is send out a signal to turn these devices off and on in unison to create massive fluctuations in demand for power. With enough knowledge of the power grid you could configure demand fluctuations that could overload strategic sub-stations and other infrastructure. Infrastructure for which spare parts have a lead time measured in months. The power grids of Western countries are being made deliberately brittle (by their own traitorous governments and bureaucrats) and vulnerable to these sort of attacks. If/when they happen, they will be blamed on "Climate Change".