Whether you're building on-premise software or just want to use packages as your atomic deployment mechanism of choice in a traditional bare-metal/VM infrastructure, deb/rpm packages are a nice thing to provide.
Multi-stage builds can help reduce your Docker image sizes in production. This has many benefits: Development dependencies may potentially expose extra security holes in your system (I've yet to see this happen, but why not be cautious if it's easy to be so?), but mostly by reducing image size you make it faster for others to
docker pull it.