I think a large fraction of what you’re paying for is the interface. Your phone can in theory do a lot more than a calculator, but having dedicated buttons for

I think a large fraction of what you’re paying for is the interface. Your phone can in theory do a lot more than a calculator, but having dedicated buttons for everything makes a calculator much better suited for its purpose. Though maybe that’s just because nobody has come up with a great UI concept for a touchscreen calculator.