"There are two things in a building:
its use and its beauty;
its use belongs to the owner, its beauty to everyone;
so we go past our right when we destroy it " (Victor Hugo)
A building is the expression of the numerous soul of a "country", the picture of a lived culture. It integrates with an architectural environment which it is necessary to respect.
They cannot, in restoration, work as in new building. But they can bring actual comfort without following in group.