With a website builder, you rent a page on a shared platform: while you pay, the site works; stop paying, and it disappears along with everything you built. The platform's rules can change at any moment, and you have no say in it.
Here you get a full-fledged site on the Shopnseo platform: your own admin panel, your own structure, built-in optimization for search engines and language models, a user account system. Behind the server stands a specific representative you can actually negotiate with, and for an organization that needs its own dedicated environment, the platform is installed on its own server — that's the Server tier.