Two examples that come to my mind:
1) [iemguts/canvasselect] allows to (de)select objects simply by index. No need to emulate mouse selection with "mouse" and "mouseup".
2) canvases/objects can be moved around with [iemguts/canvasposition] resp. [iemguts/canvasobjectposition]
Are there any other use cases for "mouse" and "mouseup"?
Hi. My 2 cents
    
Personally, I use mouse and mouseup messages to forward
      multitouch events into the patch, received  from my multitouch
      linux laptop. 
    
 If those messages were blocked, all my multitouch ecosystem
      would be out of order :-) .