(On the other
hand, who uses a calulator any longer? For me,
anything more than one or a couple of multiplications or divisions,
and it's straight to the spreadsheet app kept idling in the
background.)
Me, for example.
First, calculators are a lot more physically portable than "the
spreadsheet app kept idling in the background" (which in my case is
rather different, but I'm using it to refer to any kind of calculator
facility on a computer). I have calculators in parts of the house
where there is no computer handy.
Second, the user interface is, at least in my experience of calculators
and programs that can serve for similar purposes, substantially
better-designed for the task. Part of this is the physical
portability, but not all; a general-purpose keyboard is not the best
input device for calculator functionality.
Third, it's a lot easier to do things in other number systems on a
calculator than on a spreadsheet. That isn't to say it's impossible,
it's just hard.
Peace... Sridhar