I don't know how much things have changed in ten years but when I was in university I simply couldn't find a computer calculator software that had the same easy to use UI as my HP 40gs or even a basic Casio fx-991ES.

Sure I could fire up Matlab with the Symbolic toolbox or even Derive under wine but nothing came close to just typing in what I wanted and pressing a button. I guess it's more a matter of dedicated physical buttons and muscle memory.