At one job, I can have my phone on me as long as I don't abuse the privilege (e.g., no personal phone calls in patient areas or surfing on Facebook). So I do get to use some pretty helpful apps during the workday. Also, text messaging is how a lot of the staff communicates with MDs and each other if we're not able to reach someone at their desk/office phone.
Another job has a strict ban on cell phones. As having the job is more important to me than having an app at my fingertips, the phone stays in my locker.