It didn't refer to any standard about how this signal should be sent so different browsers could send completely different information.
It didn't put any requirements on businesses who receive this signal. They are free to completely ignore it just like Do-Not-Track, and most will.
Even if a company wanted to comply out of good will it doesn't define even vaguely what people are opting out of by toggling this setting which would lead to confusion as different sites would implement different things, and different browsers and OSes would describe it differently.
It was literally mandating a dummy button.
[1] https://leginfo.legislature.ca.gov/faces/billNavClient.xhtml...