A non-developer choosing between a web app and a mobile app is not making a cosmetic decision; they are choosing between two different delivery stacks, operating constraints, and maintenance burdens. Mocha and VibeCode diverge sharply on that job because Mocha was aimed at quick web app generation, while VibeCode is oriented around producing mobile experiences that have to survive native packaging, device APIs, and store rules.
That makes this a useful comparison because the web-versus-mobile fork exposes the failure modes that actually matter. If the product needs login, permissions, data integrity, notifications, offline behavior, or app-store distribution, prompt quality stops being the main issue and platform plumbing becomes the whole game.