This is cool because one of the most difficult things to do in these types of systems is represent context of a program at any given time: especially when most

This is cool because one of the most difficult things to do in these types of systems is represent context of a program at any given time: especially when most programs maintain their context using the stack (plus quite a few other abstractions depending on the programming methodology). Using a spreadsheet as your "context" is one way to solve this problem.