I think part of the Vizla fight was that Vizla openly challenged him to a duel, one on one, and openly remarked how the Blade itself was the death of Many Jedi.
It looked to me that Barriss gave Anakin quite some trouble, kicking him, force pushing, disarming and so forth. But yeah...I know.
Yes Obi-Wan did beat Vizla, but just the fight itself Obi-Wan should have just speedblitzed him or taken the saber from him with a force pull or even just restrained him using the force. But then again...wouldn't have been as entertaining...but still.
Maybe to prove it to himself, or Satine, that he could take Vizla, but yes, entertainment value. It's the little things you have to look for in the fights...