Furthermore, floating labels add unneeded code weight. And add to code complexity, which creates more work for QA in addition to dev.
Also, an argument for floating labels is to save vertical space for small screens. But since the pattern requires vertical space for the label to move to, the point is moot.
Floated labels can be tricky to implement and support (especially to ensure accessibility). I’ve also seen usability issues with them even from leading companies. For more, see: http://www.webaxe.org/floated-labels-still-suck/
Great article, thanks for writing!