Well mediafire will make you download a file.
Hosting a C2 game requires to give access to the media files and several .JS files.
Putting all your project on dropbox and giving the public link to the html file allows you to play directly the game. Mediafire propose no such service.
Moreover, for a little file, like a capx, you have to go to a mediafire page and click a download link.
With dropbox, you simply give a link and it directly downloads the file with no further clicks or page loading.
So for hosting games DropBox > Mediafire.
For hosting capx DropBox > Mediafire.