^^^ Yeah I was gonna say.
Today's smartphones and other gadgets are heavily reliant upon cell towers and wifi networks and cloud storage and GPS connections and the internet for functionality.
How limited would a smartphone or tablet be without *any* connectivity network support, solely operating on its own?
Communicators and tricorders are largely self-contained units, not needing extensive infrastructure to operate.
Plus, I suppose they are designed not for general public use but for specialized Star Fleet missions.
Exploring strange new worlds, where no man has gone before, you'd want rugged reliable sturdy independently functional hardware. It may not be the latest and greatest that 23rd century tech has to offer, but the best option when needed on the final frontier, well beyond the nearest help desk.