A Steam page's job is to convert a scroll into a wishlist in about two seconds, and the capsule image is doing almost all of that work before a player reads a single word. Most indie teams have exactly one shot at this because they can't afford to commission ten different capsule concepts to test. AI generation changes that constraint.
The actual advantage: options, not a final asset
The real value of AI tools here isn't "generate the final capsule art," it's generating fifteen rough concepts overnight so you can see which composition and color direction actually stops a scroll, then commission or refine the one that works. This is closer to how professional marketing teams already operate, testing many concepts cheaply before investing in one, just newly available to a solo developer's budget.
Where generated assets are fine to ship as-is
Screenshots aren't the place for AI generation, they need to be real captures of your real game, misleading screenshots are both against store policy and the fastest way to earn refund requests. But supporting marketing material around those screenshots, background textures for a store page banner, social media post templates, is lower-stakes and fine to generate directly.
Trailers: assistive, not automatic
Full AI-generated game trailers aren't there yet for anything beyond a rough placeholder cut. What does help: using AI tools to quickly test different music tracks against your real gameplay footage, or to generate several possible pacing structures (open on story vs. open on gameplay) as an animatic before you commit real editing time to one direction.
The metric that tells you if any of this worked
Wishlist conversion rate from page views, visible in Steamworks, is the only honest scoreboard. Generate variations, but actually check whether a new capsule or trailer cut moved that number before assuming the AI-assisted version was an improvement. Marketing intuition is wrong often enough that skipping this check wastes the entire exercise.