i'd venture a guess that they were given up on since they couldn't be styled like all native elements. also, check boxes remove one from whatever design the UI is meant to have. if you're recreating the look/feel of a control panel with buttons/knobs/sliders, check boxes are not something you would find. a flip/toggle switch or push button is common for 1/0 binary type options. a knob or fader allows for values between 0-1. you just don't see too many check boxes out in the wild.