Directly from the flutter documentation:

>> What scenarios are ideal for Flutter on the web? Not every web page makes sense in Flutter, but we think Flutter is particularly suited for app-centric experiences:

Progressive Web Apps Single Page Apps Existing Flutter mobile apps At this time, Flutter is not suitable for static websites with text-rich flow-based content. For example, blog articles benefit from the document-centric model that the web is built around, rather than the app-centric services that a UI framework like Flutter can deliver. However, you can use Flutter to embed interactive experiences into these websites.