Comment by cefboud

For languages that support cross-compiling e.g Golang, the Docker docs recommend cross-compiling natively and copying the resulting binary to the various platform images. binfmt_misc with QEMU is needed for languages that don't support that, or when you want to run a binary from the base image. For example, if you're building a x86 Docker image on ARM and you run `RUN apt install` in the Dockerfile, you're essentially running an x86 ELF on ARM, and that's where QEMU/binfmt_misc step in.