Whoever did this just killed that as an information channel as both the devices and the network are now compromised.
This is also true for Hezbollah. They must now distrust their own network, equipment and procurement channels. The reshuffling resulting from the casualties will make the organization less effective, at least temporarily, thus delaying any attack plans and allowing moles to rise through the ranks.
Loads of pagers are passive, receive-only devices. There's a reason why there's a common distinction between "pager" and "two-way pager".
I'm not sure if thats true, they just need to start cracking open their shipments of pagers and looking for explosives.