This may have been brought up before but I could not find it.
When you have the Sorter to appear as Menu bar extra, the ability to tear the drop down off (such as with the Fantastical drop down) and then be able to have it stay above all other windows and/or move it around the screen as desired.
When you have the Sorter as a Dock Tab, be able to grab the tab and move it up, down or to the opposite side of the screen (as you can with Yoink). Then the ability to tear off the pop out and be able to have it stay above all other windows and/or move it around the screen as desired.
I know I can use a key stroke to pull up the Note tab but I never remember keystrokes!
Examples, Yoink, Trickster and Fantastical 2.