Static does not mean simple
A statically deployed marketing site can still deliver sophisticated interaction, animation, rich product storytelling and strong search visibility without a permanent application server.
Why it can be operationally attractive
Static files are easy to cache, easy to deploy and reduce the production runtime footprint. Dynamic business actions can call separate APIs when required.
Design around the boundary
Keep content, SEO and interface behavior static-friendly. Move lead capture, authentication or transactional actions to explicitly configured services instead of quietly depending on server rendering.