I'm just curious - why have an "Adult National" competition that includes beginner level skills? Surely only local skaters would attend at that level?
Adult Nationals has testing requirements, and no beginner events are offered. The lowest level offered in Freeskate is Bronze, Bronze in solo dance, Pre-Bronze in partnered dance (but must have passed at least the full pre-bronze test, I believe), and Bronze pairs.
What is being discussed is Adult Sectionals. The true "Adult Sectional" competition is only the qualifying events - i.e., the Championship Silver, Gold, Int/Nov, Sr., and dance and pairs events.
Each Sectional generally hosts a non-qualifying competition simultaneously, which usually uses the same name. That is where the beginner and open events are offered.
Generally, people even at a lower level (or those at higher levels that do not compete championship) attend because going to an all-adult competition is truly a unique experience, very different than even local competitions that have adult events. You have people come in from all over for those events for many reasons, and often one of those reasons is it's the only competition they may have someone to compete against. You meet many new people, it is a goal to work towards throughout the year, and it allows you to showcase your skills while having fun. The same is true of those who only compete open events at Adult Nationals.