What is it you're actively using PDAs for?
I have major, major issues with distractibility, so having a device that only makes sound when something actually important needs to happen is helpful. I find even with notifications reduced on my phone about half the time when it makes a noise it's not actually important. As such I turn off my phone for the majority of the day.
Additionally, once I clear a notification on the Palm it's not like I can then fall into web browsing on it.
Whether one believes it's a thing or not, I've been diagnosed with severe inattentive ADHD and I find simple, limited use devices really do help me stay on track.
Christ, being able to stick it on a dock and hit one button to mirror your entire device onto your desktop was great.