> In the short term, it's a smart strategy for Israel, but they've likely opened Pandora's box in the process.

Absolutely. From today on, this type of attack will have to be considered part of the arsenal.

While building thousands of explosive communication devices and swapping a large shipment requires substantial resources and intelligence, the actual "sophistication" of today's attack seems to lie in the fact that the perpetrator managed to specifically target a clandestine adversarial organization.

If you don't care about that last part, I don't think it's completely out of reach for a hypothetical "state sponsored terrorist organization" to have a thousand smart phone explosives shipped into a target market, say the European Union or the United States. Such an attack, if successful, would be devastating.