The real advantage to plotting via code isn't just better visual styles, but mass plot generation. The process in Excel:

  1. select data
  2. select chart type
  3. customize chart
  4. export chart (for Word doc inclusion)

can be very time-consuming repeated with dozens of charts. Each time someone wants to alter the style (a manager's arbitrary decision to use three decimal points instead of two etc.), steps 3 and 4 must be repeated for each chart. Or data get corrected in a way that alters all values and everything needs to be re-exported, and the axes need to be fixed. These "little" items really eat into time as data are massaged and report drafts get reviewed and corrected.