In the list of Submission Types, include "Checkbox" as an option. This would allow course developers to turn the Assignments tool into a checklist for what students must complete in each Module. This would enable completion tracking to cover any Assignment, whether a submission is required or not, and allow users to indicate to themselves and their teachers that an activity is complete.
Assignment: Complete the Unit 1 Readings
Due Date: Jan 1st (end of Week 1)
Submission Type: Checkbox
Student knows that readings are required. Can track completion of readings with the same tool used for submission of papers and discussions. Student completes readings and checks the box on the assignment page. Student's progress tracking is updated. Professor can see which students have or have not indicated that their readings have been completed and can nudge students to complete the readings as needed.