Dragging around, I finally experienced Google Stitch today.

To summarize,
it's useful for quickly validating ideas and generating relatively complete design drafts.
But right now, it still heavily depends on how prompts are written and how the design system is tuned.
(1) Model Selection
Stitch has three models: 3 Flash, 3.1 Pro, Nano Banana Pro.
The first two, even with complex prompts, generate relatively quickly, but Nano Banana takes a few minutes to produce.
3 Flash focuses on speed, so the quality of generated designs is average, and many details are easily simplified.
3.1 Pro understands the logic of prompts and design, making layouts more reasonable and components more standardized. However, it can sometimes add unnecessary elements, making simple interfaces more complicated.
Nano Banana Pro, although slower, emphasizes high image quality. The textures in text, charts, shadows, and cards are much better than the other two.
So, if you're using Stitch to assist with design, you can first use 3 Flash to quickly generate designs with different styles and layouts, then refine with 3.1 Pro, and finally complete the final design with Nano Banana Pro.
(2) Design System
Stitch allows selecting a design system to freely adjust the style of the design draft.
Additionally, you can input a URL, and Stitch will automatically fetch the design style associated with that URL.
Mainly focusing on color schemes, fonts, corner radii, etc., it can be used to generate designs with different styles and quickly verify which color combinations look good.
(3) Generating Design Drafts from Sketches
A powerful feature of Stitch is its ability to generate a more complete and refined design based on sketches, which can be used to quickly verify the reasonableness of sketches and optimize solutions.
The main experience is in design; other features like importing into AI Studio or exporting code are not discussed here.