Do you limit your submission types to Annotation or File Upload? I'm not sure how the automatic submission would help you as it does with Quizzes. If you set availability dates, students are no longer able to share/upload work.
An automatic submission on the deadline, we have no late submissions, for text based assessments, would massively reduce the number of students that miss the deadline by less than a minute because they can't locate the Turnitin tickbox or for any other reason.
No matter what does perfectly emulate in-person exams. Also this helps to argue in favour of continued use of the VLE for all final exams. The decision to not provide the capacity to make late submissions was also in service of offering a direct facsimile of the in-person experience. I am pretty certain that the option would be of use to many in my circumstance where the argument to not use the VLE for formal exams is taking place this year.
I'm very much in favor of this. Would be a great help to me, too.
Also having the ability to not allow files to be attached to the comment section of the submission would be very appreciated. I've got a lot of students that habitually miss deadlines for assignments, because they know they can attach a file to the comment section after the deadline so they feel justified in taking more time to complete work and submit at their leisure, play dumb about the whole thing - sometimes blaming technical issues from preventing them from being able to submit properly when they had simply missed the deadline... and even after being warned not to do that in the future...