What it is
The job it was built for, and the job it is not for.
Nano Banana 2 is an image model, built to generate pictures from a prompt and to edit pictures you already have. It sits in Google's Flash line, where the trade being made is response speed against the heavier Pro models. It is not a general reasoning or coding model, and it is not built for long-form text output, the text side of it exists to describe and direct the image work.