It's not meaningless because it makes hitlery look like a petulant follower. If she demands to be let in, it is being let in to Trump's debate, and he'll beat the hell out of her. If she avoids it, it's because she is a coward. From Bernie's perspective, he's losing anyway. Only a hail mary pass can save him anyway. He's got nothing to lose.
Any way you slice it, Trump wins and hitlery loses.