Here is a more representative video. Some of the costumes are really good, men and women. Its a high bar to come up with a decent costume. If you are extremely ugly or extremely good looking, investing that time in a costume makes sense.
There are a lot of ordinary girls who tart it up for these conventions, and if you like that look it might bump them up a point or two.
Also, there are multiple conventions in different cities, sometimes several in the same city. Look for Comic Con, Dragon Con, Super Friends or Super Hereos conventions, and Anime conventions. These things are well attended because its another excuse for women to dress up half naked and get attention.