Lizards also don't breathe fire, so we're already not going for pure scientific accuracy. The idea for Shed Skin has been floating around for longer than Sebille's source skill, Nivv came up with it a while ago and I've been promoting it as a more useful racial than the Lizard's Firebreath. (Admittedly, I also dislike Firebreath for my own personal preferences when it comes to lore.)
It's quite true that it can't be used when you are under hard CC, but there are enough other negative statuses for which this would be helpful, especially for cursed-surface status effects.
