Humans are also able to drive with vision only. Same sentiment as Hotz from comma.ai has.
I also think that radar will be a no brainer and make it better over all (night, fog) but I'm not sure if it has to be a must.
Perhaps in 20years when you have overall very good car AI the non radar version is always behind but we are far away from this market saturation. Probably more than 20 car iterations and more.
For emergencies there are proper laws.
And no your taco bell getting cold is not a good reason