[Symmetry]

I'm not sure why you'd worry about completion rates. When I've taken online courses I've completed all the lectures and their associated exercises. But if I'm taking a course it means I have some end in mind for the skills it teaches me and that makes any final project or exam superfluous.

[Pamar]

I have to disagree: for me the final project was important to immediately put to the test the things I had learned. And - as I explained above - if the course has peer-grading (almost a given if it has a final project, because you cannot automate the evaluation of a project) you learn even more by evaluating the ways other approached their solution.