Interesting. I tried this out. I really like the whole idea of collecting things in a block to have some sort of access to on an unrelated page. I noticed how you can use this to move menu items about, I'm just unsure why it would be more useful then the current drag-and-drop system in /admin/build/menu.
Try the current system with a couple (hundreds of) thousands menu items and you will see :D
I cannot see any use for the "Path .." radio button.
Because I have not coded any other button in there :) though I might.
I'm wondering what you envision this module better enabling someone to do?
Any time when you need to administer things which are one in a huge lot, it's very useful. Administer path aliases when you have a million of them. Create node references. Etc. About collections, that's a different usage than what I envision here. Screencast ... I could create one, sure.