Going on a tangent here, but does anyone else also agree that BuildRoot is much, much nicer to work with as a dev than Yocto? I've had to work with both and BuildRoot was easy, just like building a Linux kernel with 'make menuconfig', whereas Yocto was downright painful.
They both get the job done but I find that yocto recipes are more tractable. You see clearly what comes from the main git tree and what patches a vendor adds on top.
I've seen some really ugly chimeras built with buildroot as a base..
I have used buildroot for an initramfs. If you have configured a kernel before, you get going in an afternoon.
Yocto is definitely more flexible, which can be a curse as it gives architecture astronauts more chances to split up all the stuff it several repos and dozens of files.