It is still new, and not all things work. Progress is made.
Is there an SD card image available for download? I see an email address, does that mean you have to email that person to get a working Debian SD card image?
No, you just can download that 490MB file with the tar.xz extention and unpack it on your computer. Then you could dd it on a SD-Card.
What do you mean with the term “working”? It just boots debian sid without graphical interface. Not much more. It is still in development.