Plus, VHF signals can get where no LTE or satellite can arrive, even if you are two floors underground. Downside is that anybody can read POCSAG, especially nowadays with inexpensive SDR receivers...
There are a bunch of POCSAG paging products that support their own flavors of encryption. Unication has a few that support AES encrypted messaging. You keyload it at the same time as the rest of the pager setup.