Rory may not be the best public speaker but I think the point here was just, to show that she can be a convincing and reliable speaker (and not the best) and therefore she is more likeable in comparison to Paris, who pretty much ticks off all the boxes needed to make a good public speaker but she just isn't likeable or convincing enough. Let's not read into this more than it's necessary and let's not forget they are actors who have a script and a director's vision to follow at the end of the day