I think having an archive with all the media generated by funded proposals is great.
It would make it easier for teams behind nounish and Stoopid Buddy documentary (and future teams) to get the media they need, so they can focus more time on the creative process and not aggregation. It would be even more powerful if the submission were coupled with a cc0 license agreement (or an option to choose cc0 vs other licenses) so people would be reassured they can use the media without any fear of licensing.
I’m not sure how the banner contests play into this, that part seems unnecessary to me.