There is something fundamentally evil about turning communication devices into bombs. To turn the integument of the modern world, the ability to interact with one another at a distance, into being something that could kill you and the people around you, it's just wrong.
You could say we were already there. Plenty of people out there in the world think about how making a phone call or posting a video could bring down a drone strike on their heads. Hezbollah ditched cellphones out of fear they could be easily spied on. But for the danger to be immediate, to be in your hand, to have been there for months by your bedside, in the radio on your belt...
The pagers yesterday beeped before they exploded, to make people bring them closer to their faces. We're conditioned to pay attention to the devices in our pockets. They are an indispensable part of our social worlds. And they are inextricably connected to the globalized supply chains that it's difficult to even imagine securing.
It seems like a fundamentally different kind of attack, and nobody knows the consequences. Planting explosives inside thousands of devices, at some point in a supply chain? It's a new kind of terrorism that only an immensely powerful state shielded from fear of consequences can perform.