Go!! The deadlines seem to be a little flexible these days...I get the impression you can submit videos after the deadline and not be excluded. Casting seems to be an ongoing process these days.
The disadvantage to a casting call is that your video is off the cuff, you don't get to be as prepared. But sometimes that is an actual advantage! And nothing to say you can't submit the video too.
Go, have fun, enjoy the process! And best of luck!!