User blog comment:FairyRaven/Fairy Tail vs. Alvarez Empire! Place your bets!/@comment-7418318-20150915202219/@comment-24264679-20150917034323

It drys the skin out. Meaning if someone had water for skin it would just suck all the water up and if someone had metal for skin it would just rust and erode the metal. Having water body or Iron scales doesn't mean that attack wouldn't effect them.