I think it is something wrong with modern variations of checkboxes. Consider this iOS version:
It is not clear is it in “On” state or you need to click on “On” label to switch it on?
Am I the only one who think that this is completely non-intuitive?
The check box has to have two distinct visual styles telling its current state without need for the user to guess its state. IMO, old plain check mark is just perfect idiom for that, why do we need to reinvent the wheel here?