[auxym]

I'm no big fan of excel, but the modern xlsx format is "open", in that it's documented (though maybe not perfectly). It certainly is possible to read data from it using a variety of open source packages, from LO Calc to libraries like pyxl.

[baldfat]

It's not that it's open it is that all the steps are seen and can be repeated. Excel is just manual labor without seeing how the person took the raw data and got to their conclusion.