I am new to this forum, so I don't know how appropriate is for me to keep pushing this discussion, so I'll first go to my point and then I share an example from one of my courses where I found different late policies for different assignment type appropriate. The main point is that whether they don't exist or they are not enforce in many campuses late policies varies, so why have a one-size-fits-all solution? If there is a default policy with the option to change for individual courses or individual groups, that will work for those with uniform policies and those that do not have that. So why not? BTW, this is not my idea, some online software tools do that already. For instance, the software tool that comes with the book on one of my classes let you setup default late policies for each kind of assignment and then will let you override the policy within each individual assignments. If they allow that, is because people use it.
Here is my example, I teach a science class which is a part of the general education curriculum for non-science majors (the class where I use the homework platform I mentioned above).This is a large class, so minimizing manual overrides is important. One of the type of activities I assign, consists of adaptive modules meant to train students on a particular subject (not to test them), so the due date for those is before the class where I cover that topic. I can simply not accept late submissions, however, I believe in the value of the activity and want my students to still do it, even if late. I can't allow late submissions without a penalty, if I want to "encourage" students to do it before the class, but I can't just give zero to those the do it late or there will be no incentive for them to do it at all. However, once the class passed, I rather prioritize the next activity, so they are on time for that one, than the old one, so I just apply a flat late penalty on this activity (something else Canvas does not allow you to do either, but I would be ok with progressive penalty, so no big deal there). A homework, on the other hand, I do want them to do it by the deadline, or if they are late, as soon as possible, so penalties for being late on a homework are much harsher, especially because in most classes I release the homework solutions after some time, so I cannot longer accept a homework after I release the solution. In my opinion I should not be forced by the software I use to either be harsher on the former type of activity or softer on the later. Not all courses are the same and not all assignment are the same, we should trust that instructors know what they are doing and give them some freedom to manage the class.