AOC is popular with Democratic Primary voters across the spectrum. She has an even higher favorability rating with Warren supporters than Sanders supporters. To say that her endorsement is not important is flat out wrong.
She is the most coveted endorsement outside of former Presidents according to polling of Democratic primary voters.
He underwent a common procedure to increase his blood flow and looked better than ever on Tuesday night. He still looks in better shape than the bumbling Joe Biden next to him. Sanders is clearly the best candidate and it shows every debate when the discussions consistently revolves around his policies and ideas.