I mean, to be a bit more charitable, when you have use cases that require server pushes, the traditional server rendered pages don't work so well, and that is where SPAs make sense. Mind you, a lot of the frameworks for rendering server side have started to include natural ways of handling those updates (Phoenix Liveview for instance being one I'm familiar with), that makes it so you likely don't need an SPA in those situations, but there are still use cases where an SPA may be simpler or may enable a UX that otherwise would not be possible.
But to the apparently snide response to my original comment, while there may be reasons for SPAs, there are also plenty of uses of them that could be more simply done via server side rendering, especially with the place such frameworks have moved towards, in enabling server pushed updates.
