You could, but the biggest benefit of staged builds (IMHO) is that you can use a heavy base image for the build process (classic Ubuntu for example, where it's

You could, but the biggest benefit of staged builds (IMHO) is that you can use a heavy base image for the build process (classic Ubuntu for example, where it's easy to add repositories and install dependencies), and a very small image for runtime (i.e. Alpine, busybox). I find that it's easier to debug the build process with a "standard" distribution.