Avenatti was a novelty because he had the ability to make the sitting president fire up a twitter rage storm at 3:00am just by making a few comments earlier in the day.
The idea that he was some "Left Hero" is manufactured by the Right. Just as Avenatti being a solid candidate for 2020, that started because of Steve Bannon making the comment during some interview, iirc, on CNN. Which to Bannon's credit, was kinda clever.