I was thinking about this and one way of thinking is what u said. We already allow sale of spaceships which have non-zero failure rate. So we don't necessarily need zero failure rate self driving.

But a problem with cars is, usually ur malfunctioning calculator just harms u, but a malfunctioning car will affect people who don't agree with ur choice of driving non-zero failure rate self driving car.

So it is not a personal choice anymore.