Hey again!
It is actually due to a historical reason actually! I used to take the Category as the TreeViewItem title automatically in the older versions. You are right, it should no longer be mandatory... However, I also use it in places like Nebulograph to differentiate between objects with the same name, so I feel it is better to keep it.
You can create your own Element templates in Options btw. Select Default for example and Click the +, and there you may create your own Character template (although it's gotta be a different name, yeah).