To answer my own post, you can make a bootable usb this way (URL) and by basing it off the
full DVD iso
the boot: prompt will be available to add the btrfs string option to it.
and there I see:
Note that the liveusb-creator GUI, however, does not support putting the DVD installer on USB.
Ok, so I need to use livecd-iso-to-disk to put the DVD to the key so I can btrfs my Asus laptop.
Note, I think you can install to ext4 and then modify the existing ext4 to btrfs but this not optimal so
I didn't want to do that.