Submit project button - app academy open

I have been using the free online curriculum for a number of weeks and find it very helpful. I have some questions about submissions via the “submit project” button at the bottom of project description pages, which must be used in order for the page to be marked as complete.

1- Is there any reason for non-paying users (accessing free online curriculum) to submit completed assignments?

2- Does App Academy actually want such submissions?

3- What happens to these submissions after they are uploaded. Does App Academy use them for anything, or are they just sent to trash?

If someone from App Academy could answer these questions, I would be grateful. Thank you!