Well, we bought a four bedroomed house when we retired and at least three or four times a year every room is in use. Neither of our children live near us, nor, many years ago, did our parents, so we often put up the whole family, now without parents but with grandchildren. The fact that a room is not in use every day does not mean that it is not needed.
My parents bought a two bedroomed bungalow when they retired and deeply regretted it and in their 80s seriously considered moving to a bigger house where they could have a combined workroom/office that did not need to be a bedroom as well, plus three bedrooms so that their children with their grandchildren could all stay overnight rather than just make day visits or individual overnight visits.
What right have these people to dictate to us how we live and what accommodation we need. The reason Housing Benefit payments have soared is because rents have soared, not because more people are occupying accommodation deemed to be to big for them. I understand that some people who have moved to smaller accommodation are paying higher rents, so that this policy is increasing the amount of housing benefit some people are now receiving!!