This is on a Debian system.
I have had the compression of files and contents into individual folders working fine but not with the date added to the file names. Removing the date part, it works as it should.
I'm pretty sure it's something to do with syntax as I've based it on a couple of examples I came across...
Here's the relevant code:
for i in */; do tar -zcvf "$i $(date '+%y-%m-%d').tar.gz" "$i"; done