Here's why: For me, it appears to attempt to solve the problems of: a calendar, reminders, and school-related task management.
During the first week of each class, I "process" the syllabus by adding the major assignment due dates (usually 3-5 over the course of a quarter), and exam dates to my Google Calendar. This is a pretty quick process. It's so little overhead that I think setting up a sharing system with others to try to share the data is actually more overhead. (I have used a setup like this for 10 years myself, and I expect most students have something similar.)
I get text-message based reminders a week in advance for these special events (a separate calendar from my usual one for easy color differentiation). The professors always list and review contents of major exams and details of upcoming projects already anyway.
And finally, my student / project tasks are managed separately in another system alongside all my other projects and areas. It never made sense to me to separate the student side when really my entire life is project-based. For this type of system, I've used text-based GTD, Wunderlist, Taskpaper, etc.
That said... If I could sign into your app the first week of my class and have all this done automatically for me, I would be very happy.