To add to your point regarding additional functions inherent in smartphones: pagers do one thing. They’re relatively simple devices. Simplicity means that there are fewer things that can cause the device to function incorrectly or fail to function altogether. In hospital communications use-cases, this is a huge benefit.

Additionally, pagers are relatively inexpensive. Therefore, it’s much more effective to have multiple spares available for distribution compared to smartphones. If a pager is inoperable, it can quickly be swapped out with a backup while the original is repaired or replaced. Smartphones do not carry that benefit.