You're all forgetting the reason why pagers were being used instead of mobiles: geolocation.
Any mobile phone can be geolocated, either through GPS technology, phone mast triangulation, or monitoring of local wifi signals. If you can geolocate a phone you can locate its owner and kill him.
Pagers don't work that way. Pager signals are broadcast simulataneously over the whole pager network. It's a one-way signal outgoing only. No GPS, no triangulation, no wifi tracking. Untraceable
That is why Hezbollah had switched to pagers
Any mobile phone can be traced, a pager can't.