The cars don't see cyclists and pedestrians consistently or in time or interpret them correctly.

All Tesla sensors have been reduced to just cameras which can fail in weather, fog, rain, snow.

Remember Musk outsources safety for savings/profit as someone else's expensive problem.

A beacon could save lives for those who are active and willing to carry it as one extra level of protection.

But like I said the problem is spoofing for those that want to be an irritant.