[cdsmith]

There are various arguments for the benefits of functional programming. But that's really beside the point here.

In this particular case, the point was that I created an educational tool for teaching mathematics. It happens to involve a programming language; but the goal isn't to train computer programmers. It's to teach math. So the language used is one that lets you describe functions and quantities the same way as you would in math, and mostly avoids the need to think about a computer doing some sequence of operations.