As with many things, the answer is it depends on what you do. I inherited an app that serves about 1m requests a day, and server-side rendering of the HTML is one of the reasons why we're going to decommission this app, as the performance of the server-side rendering here is atrociously bad/unacceptable. We reimplemented many of the same features in a SPA that does a lot more overall and the performance difference is night and day between the two.