It could have been improved by some performance benchmarks showing cross compilation performance in comparison with this emulation based solution. I find it hard to believe it makes sense to emulate when native performance is available.
For example, with the RaspberryPi I can grab a Raspbain image, add binfmt and qemu on my host and with a few small changes to the image chroot in to a ready made build environment for the Pi that's faster and more convenient than compiling on the Pi. Setting up a cross compile environment for the Pi is much harder.
Docker is totally unnecessary BTW.
Modern languages are even easier. I can build a Go binary for the Raspberry Pi by setting one or two environment variables; "GOARCH=arm GOOS=linux go build ./whatever". Wonderful.
The Raspberry Pi has improved since the original. I recently needed llvm compiled from source and it only took on the order of hours on a Pi 4. (GCC was unusable, though; uses too much memory. Had to use clang from the package manager to build a new LLVM. The efficiency was impressive.)