Accurate data typing (never confuse a string with a number)
Maybe be circular but: always loads correctly into Excel, if you want to load into a spreadsheet you can add text formatting and even formulas, checkboxes and stuff which can be a lot of fun.
Excel does that type coercion if you import from CSV. If you export pandas data to XLSX it adds proper type information and then it imports properly into Excel and you avoid those problems.
