Sure, but I'm intimately familiar with the semantics of the programming languages I use. It takes the same effort to insure floating point versus integer computations in the Python REPL as it does when writing a Python program - which is not much.
I'd rather use my existing knowledge than learn how to interface with something that is probably not as robust or as well designed.
Also, I have to admit that python 2's default behavior regarding integer division is not what one expects from a calculator (I expect 3/2 = 1.5).