Its completely fine if you don't submit for any reason, you aren't being forced to submit. Some ranked game jams only allow those who submitted to rate other peoples games , although I'm not sure if its that is the case for this jam. Hope this helps clear things.
If you join the jam but don't have anything to submit that's fine. You'll still be able to view and play games, as wellbas post comments, you just won't be able to rate them. Last jam we had over 860 people join but only around 280 games were submitted
