Store your own work files... (?)

I'm making a site for creators, and the way things are, it just works out easier for me (and hopefully users) if they store their own work files. ie: they can download their projects so I don't need to store it for them. So whenever they want to work on a project, they just upload that file, make changes to their project, and download it to save it locally. Is that just a horrible idea? I don't see a problem with it and it sure saves a lot of work and expense on my end.