Why do they need an app server at all? The website, to my initial glance, seems to be a brochure for the desktop product. Surely static pages and static assets

Why do they need an app server at all? The website, to my initial glance, seems to be a brochure for the desktop product. Surely static pages and static assets would be even more resilient against a ddos since it's just bog standard webserver streaming out the static resources. Mount a memory based fs and conventional disk latency concerns become mitigated, too.