Most AI crawlers don't run JavaScript — they read the raw HTML response. A client-rendered SPA looks empty to GPTBot, ClaudeBot, and PerplexityBot. SSR (or static pre-rendering) is the hard prerequisite for being indexed.
Shopify themes are server-rendered by default, so native theme pages are fine. The risk surfaces when merchants embed third-party app iframes or client-only widgets that contain the key product data — those never reach the AI index.