It is a weird line of reasoning though. Converting this to a living space isn't the same as buy to let etc, you'd be creating new housing where there isn't any.
The issue in the UK isn’t specifically a lack of housing, if a home builder built a new estate of houses, only a small proportion have to be affordable housing, the rest come in at the ridiculous prices already in place locally. A business building 200 new houses in an area won’t bring down the house prices down at all.