You are thinking of worth and value only in the monetary sense, and the person you are responding to is referring to a house's ability to be valuable to individ

You are thinking of worth and value only in the monetary sense, and the person you are responding to is referring to a house's ability to be valuable to individuals, even if nobody else will pay for it, because it provides them shelter, satisfying a basic necessity. This is most of where its monetary value comes from (obviously not universally true, many properties have simply become investments), and its monetary value would probably only completely evaporate if the house were so degraded that it could not function as a shelter. The monetary value of most houses is rooted in their ability fulfill a basic human need, as opposed to the monetary value of some other things, like gold or bitcoin, which are valuable primarily because of what they are worth to other people. Even if you disagree with using terms like 'worth' and 'value', you must agree that a house has utility that is not affected by its market price.