They’re already discussing banning them in several states, and they’re not actually 99.9% effective in all cases. That’s only if they actually stay in place. But they often shift or become dislodged, especially in women who have never been pregnant before, in which case the protection rate is 0%. Many women do know when this happens, as it’s often painful, but sometimes there’s no way to tell it’s shifted. That’s why you keep hearing about “Mirena babies” a lot more than 0.01% of the time in people who have them.