Hah, I knew you'd bring that up.
Yes, I'm aware she does those things. But if you seriously believe that adds any substance to the story (aka "contribute"), especially the laughable speech to Shinji part (wait, random inspiration by some random stranger when nobody else would work, and was just lifted from Kaiji?), then we'll have to agree to disagree.
Though while she does technically exist in the movie and there are technically points that involve her, and she might even count as some kind of entity that appears in the movie, she hardly makes any difference to me outside of a prop.
It is not enough to exist and do something, otherwise every extra and bystander would be considered a character. Mari is more than this, so... a glorified extra she is.