It is nothing new having large signs advertising a product on the blank walls of buildings.
This “Peapes” clothing sign in George Street, Sydney would be something like 100 years old
In close proximity to this very old sign is an equally large new sign
I find these signs visually more attractive than a blank expanse of wall.
Given the technological age we live in the new signs for blank walls are usually digital and change message every 60 seconds or so. Provided the sign is framed by the structure behind and does not project over the top or out to the side of the building I believe they add interest and do not detract from the visual environment.
This Nova sign on the side of a building suits it environment in Hindley Street, Adelaide
Freestanding signs Billboard are a blight on the environment because they are not located on an existing blank wall and detract from the environment by a lack of context.