Most Native American Dances are highly symbolic and meaningful to the dancers. Some are sacred. The dancers do not wear costumes, but Regalia, and each piece of their Regalia has a specific and special meaning. Regalia is often passed down from parents to children.
Fancy Dancing, however, is show dancing. It was invented for The Wild West Show. Wild Bill brought Native Americans into his show, and they did some dances for the audience. But as these dances were considered too dull for the audience, a new form was invented with much more colorful costumes and more active moves.
Nowadays, Fancy Dancing is a competitive activity, with the dancers competing for prizes. There was only one Fancy Dancer at this time at this Pow-wow, and so he was not competing during this dance, but showing off.