Why is there no 'Recovery HD' listed when holding 'option' on startup, however, 'Recovery HD' is shown in terminal with 'diskutil list' command?
Holding down the Option Key during boot allows you to choose from "user controlled/defined" startup disks (e.g. your Mac O/S, a Bootcamp O/S, a bootable USB, etc.) whereas holding down Command-R during boot boots from a Recovery Partition that was created during an O/S install. It would be nice if all the boot options were available together, but alas, they are not.