The footage in the advert for the upcoming fanfests is actually from the past ones for Shadowbringers, where the director was dressing up as the new class (Gunbreaker) https://youtu.be/Plryox-p6SU

To give you a sense of what you might be going to.

It doesn't stop there, because they also go to events such as Gamescom and E3.
You grossly underestimate the game if you thought these events weren't already happening for the last 10 years.