His point is that he can use Excel and create new columns that are formulas.   In the data editors that are available in most GIS programs, you might be able to add a new column, but you can't quickly paste in a whole column of calculated values from a spreadsheet.  He is constrained to entering the values a cell at a time, or using some ag-specific calculation engine, rather than his excel formulas.  

The .Net version of our GIS engine supports both things he's after... the ability to add a column that is a formula, and the ability to paste in a column from another source.   But, it's not ready to go yet