Just got back from this, it was my first time. My 7 year old absolutely loved it. The audience had the demographics of a Monster Jam rally: maybe not majority elementary school children but probably close to it, and they all seemed really into it. My wife - who had done theater in school and was the theater critic for her high school newspaper - was way more into it than I thought she would be as she immediately identified it as a fusion of theater and sport.
Most of the action indeed happened around home plate and the dugouts but from Section 105 we had a great view of it all on the big screen on the CF scoreboard.
Banana Ball has intense pace of play rules. They get the game done in under 2 hours. Every pitch is a quick pitch and they start the at-bat before the batter's walk-up music ends. The scoring system is based on points rather than runs: the team that scores more runs in an inning is given a point for that inning. The bottom frame of an inning goes only as long as it has to: if the visitors score 1 run in the top of an inning, the bottom of the inning stops as soon as the home team has scored 2 runs for the point.
The crowd definitely came from all over, not just the DC area. If the places the people involved in between-inning scoreboard competitions was representative, we had people from the Shenandoah Valley, from Baltimore, from Richmond. There were a lot of Phillies jerseys with "Harper" on the back meaning I think people came from Pennsylvania, perhaps even Delaware. Tons of people had Savannah Banana jerseys on: the real kind they sell for $30 at the stadium, not the counterfeit ones people were selling for $20 outside of the stadium. For many this was far from their first game.
The players are all in way better shape than MLB players. Not a single Bartolo Colon or Matt Albers on either team, no bean pole Michael A. Taylors either. They're playing real-ish baseball: they're hitting and catching line drives, turning double plays, making diving catches in center field, but they're also dancing between every single inning and after every single run scored.
I think what will be most offensive to traditionalists - more than the single at-bat by a guy on stilts (that eneded in a weak groundout to 1B) - is the fact that they play music during the entire game. The walk-up song plays and then they keep playing short snippets of songs during the rest of the at-bat. The music never stops except for things like sack races between innings. This annoyed me at times but the crowd was into it. They played every genre of music imaginable, from ballpark staples like Thunderstruck and Livin on a Prayer to uncensored versions of rap hits to famous TV commercial jingles.