Time-travel debugging is miles better than the old way of placing breakpoints. For me, debugging with breakpoints was always a pain. I often skipped through stuff accidentally and had to start all over again from the beginning, or accidentally went inside some third-party library code that I did not intend to, or placed the breakpoint at the wrong spot. It was just slow and inconvenient, unlike React DevTools where you can see every change and step forward or backward, replay events and observe the state at various points without having to put watchers on every variable / expression.