I"m assuming that they need to keep the facade because of historic value or something but why not attach it to the new building? Some are saying it is laziness

I"m assuming that they need to keep the facade because of historic value or something but why not attach it to the new building? Some are saying it is laziness but it seems like it would take a lot of work to make sure this freestanding wall is structurally sound. Not to mention all the extra work having to clean two walls instead of just one (I guess it would actually be 3 different surfaces, the front and back of the facade and the front of the new building). Of course, the architect won't be the one cleaning it... So are they like this because someone thinks this looks good???