The prank/experiment in the video isn't done very well in my opinion. I would probably help both but I definitely understand why some people were hesitant to help the homeless dude especially the women, but except the stupid teenagers who walked by him like nothing happened.
But as for the question of the video, does appearance matter? Of course it does. Last month or so, I went to a bank on two different occasions, once wearing a sport t-shirt and once wearing a suit. At the first one, the woman in the bank looked at me in a manner like she didn't care much and asked me like, "What do you want (kiddo)?". However at the second one, the same woman(didn't even recognized me) looked at me and immediately welcomed me with a smile and talked to me with fancy words and used turkish honorifics all the time like Mr Sir etc in English. I felt like a rich douchey.
And I treated her very kindly as well, even the first time to be honest. Because her appearance was simply gorgeous.