FAQ: What does the type of a category mean? How do I change its icon on a Windows PC?
An eWallet category's type controls the default type of new cards created in that category.
On a Windows desktop or notebook PC, categories have 3 attributes: name, icon, and default card type. You can have any kind of card in any kind of category; the default is just what's pre-selected for you when you make a new card. The "New Category" type is just a very generic name, with the generic category icon.