Works, I have Sandisk Ultra 64GB card. Had it formatted as vfat, but I have always wanted to try using something better. Saw your question so decided to try it out.

I formatted it as btrfs when the card was installed. Normal
mkfs.btrfs -command works. If you do not suply any options, mkfs.btrfs detects sd card as a ssd-drive and adjusts options accordingly.

I copied some music (ogg-vorvis files) via scp and the media player detects them just fine.

I use only linux on all my devices, so btrfs is not a problem for me if I need to use the card with one of my computers.