What are my take off minimums?
What this tells me is that I can take off with any legal visibility/ceiling for my type of operation if I can maintain 325’ per nm climb. If I can only accomplish the standard 200’ per nm climb, I need 400’ ceilings and 2.5 miles of visibility, regardless of operation type. 

Essentially it’s saying that there’s something out there that you’ll hit if you can’t maintain the 325’ per nm climb gradient. If you can, great, go. If not, you need the increased visibility to see and avoid it.