If you create the option in Assignment tool for faculty to choose a time limit....this would make things so much easier for faculty to grade and provide feedback. 

Faculty using the QUIZ - "file upload" question type do NOT have all the benefits the Assignment tool, the speedgrader, and returning a graded file without major hoops. 

Canvas support (CHAT) answered... "When "file upload" type questions are inserted into a Question Group in the quiz, they will not prompt the option to download the submitted files. The workaround for this is to go into the quiz editing page, open the questions, add a new "file upload" type question outside of the questions group worth zero points. After this is done, update the new question and save the quiz. Then the option to download submissions should show."  OR  "you would need to allow multiple attempts because the "reupload" of the files actually creates a new submission on the student's behalf using the files that you reupload."

To me this is saying that QUIZ is NOT the tool to use for file uploads. The only reason why faculty are using the "file upload" question type is the want a "timed" activity where students access a file and submit their changes back within the time limit.