The promise
AdventureNomicon is being shaped for the GM with a messy note, a cool image, and a session coming up sooner than expected. The tool should help turn that spark into hooks, scenes, pressure, rewards, and table notes.
That does not mean outsourcing the story. The useful version gives you material you can edit, reject, combine, and make your own.
The example we keep coming back to
A cursed mushroom cathedral is more helpful than a vague promise about content generation. A good prep flow should ask what lives there, who wants it sealed, what bargain the spores offer, and what reward tempts the party deeper.
That is the bar for the build: concrete enough to run, flexible enough to belong to your table.