In certain niches, they're still revolutionary
For pilots, tablets -- and in particular iPads -- have been nothing less than revolutionary. Airline pilots have been able to dispense with tens of pounds of charts and manuals that they used have to carry with them, and private pilots (at least in the US) now have situational awareness that they couldn't have dreamed of (or afforded) ten years ago. For less than a thousand dollars, I can fasten an iPad mini to the yoke of the Cessna I fly, wi-fi attach it to a Stratus GPS and ADS-B in source, and running the Foreflight app have a moving map display of my position, with near real-time weather, and other nearby traffic. The combination really puts to shame the Cessna's built-in Garmin GPS (yes, I know the Garmin is TSO'd and the Stratus/iPad isn't). Rather than focus on what tablets don't do as well as laptops or workstations, maybe the point is that there are things they are capable of doing where laptops and others need not apply.