Well, I've never worked in finance, but if these are like the mathematical models that I used to make predictions in grad school and for the year after grad school when I worked as a statistical analyst, I do. I presume these are predictive mathematical models, used for forecasting?

Why in the world would Python or R be inadequate for that type of work, if that's what you're implying? What do you think they lack that Excel has, other than a friendly GUI interface? Or SAS, Stata, or SPSS (all of whom have versions that they market heavily toward finance).

No, these are not mathematical models used for forecasting. In this context, "financial statement forecasting" means making up financial statements. Something like this: https://mycourses.aalto.fi/pluginfile.php/144740/mod_resourc...