There are many reasons why people buy cars. Having already made the decision to buy one, comfort is, however, a reason people choose one model over another.
But more fundamentally, comfort is the only reason to buy a car over some alternate means of motion, as it cannot do anything more
, or more efficiently or affordably or faster, than a suitable combination of the alternatives - it can merely do it more comfortably (including the comfort of providing a compromise package of features from all the possible alternatives).
No doubt for some people, that is true.
But where there is no adequate mass transit, in rural settings were there is no mass transit at all, and when people have to frequently move things that cannot be taken on mass transit, there may be no affordable alternative. Those factors have nothing to do with comfort per se. They have to do with transporting people and cargo over certain distances within certain time frames according to a personalized schedule. Do those sort of things often enough and cars become the only affordable and available
means. The question of what alternative might perform the same functions more efficiently is academic, if there are none available to the people who need those functions now.
There are other reasons why people own cars that have nothing to do comfortable transportation or logistics.