Looks awesome. But who really uses a CD for live distros in this day and age? A flash drive would be more apt example. This made me think about how traditionalist large parts of the linux community is. :)
I'm a Linux noob, I've played around with some live CDs. The other day I tried to set up a flash drive to work the same way as a live CD. I did get it working eventually, but it was a surprisingly bad experience. Some of the flash drives I created didn't work at all, one of them booted a couple times, then stopped working, the boot process would vary from one boot to the next, etc. In my experience, live CDs "just work" in comparison.
It's really super easy. If you're creating the bootable USB stick on a Windows machine, use RUFUS ( https://rufus.akeo.ie/ ). It's about as straight-forward and noob-friendly as it gets. A single window, options in plain English. If you're creating the bootable USB stick from a Linux machine, use Etcher ( https://www.etcher.io/ ). Also very user friendly and simple. It's even distributed as a downloadable .AppImage file, so it's a double-click install on most distros. On Mac OSX - sorry, no idea, haven't used one since Apple IIe's in middle school, but I'm sure there is something similar out there for OSX (and if nothing else, you could probably get dd working in a terminal if you had to)
EDIT: Forgot to mention that RUFUS on Windows will automatically detect which versions of syslinux (the low-level booty-BIOS-y stuff) the .ISO that you select uses, and sets itself up accordingly. It can even use a newer version of syslinux if the one supplied in the .ISO is outdated. Really solid software.
RUFUS is fast but Yumi is best if you want a swiss-army-knife style bootable USB stick with multiple images to choose from, including Windows install DVD images. It also supports setup on an existing USB stick you don't want to completely wipe.
UNetBootin seemed to break a lot of images back a few years ago when I used it. Rufus actually scans the image and makes sure it's using the correct bootloader / filesystem type.
Me, every time I do an install. I've got a ton of DVDs left around. I've had USB devices designated as OS install devices, but those always end up repurposed or given away in the months/years between OS installs...but I don't have much other use for the DVDs anymore, so they're always available.
Security reasons. If you boot in a hostile environment you don't have to worry about anything attacking you, hiding in free space, etc.
Of course, this assumes the firmware is secured too; aka Bad USB.
An OS read from a CD player that's read-only won't have this issue; that said, even if the CD is burned and all the free space too, it's likely you could introduce an exploit onto the CD by editing the encoding already on the CD by putting it in a CD player that's able to read & write to it and override the read-only flag on the CD.