Overall, it's not widely used nor pushed (blue green deployments are now very common), but it still has interesting uses.

For instance, very high availability without blue-green (using a front-end that can be hot-patched), or... musical endeavors (such as live reloading code that generates music, on the go) https://youtu.be/_VgcUatTilU?si=DDfe4FN3Nw9OzRhF&t=122