Lots of vdom frameworks are more than fast enough to run business-style SPA applications, but start being very laggy for data visualisation kind of work, or any

Lots of vdom frameworks are more than fast enough to run business-style SPA applications, but start being very laggy for data visualisation kind of work, or anything where complicated animation combined with user interaction is involved. This means the developer only gets a nice declarative framework sometimes, and has to go back to a more messy way of thinking otherwise. Svelte (and some other contenders, like concurrent mode React) improve performance enough that interactive animated datavis stuff can also be done declaratively.