This was an attempt to add classical decoration or more classical additions to an otherwise plain design in order to add esthetics at a cheap price.      

People still appreciated the classical trimmings and proportions in buildings, but after the first world war, business and Governments no longer wanted to invest the money for the workmanship needed to make these creations.

Skilled craftsman were being lost as the need for their skills was becoming less and less.    

The age old ways of building were being substituted for the more modern machine reliant processes and the buildings were designed to reflect that new machine made look.

Quick, efficient and cheap to get people back to work and the economy 'jump started'. 

No longer concerned about building for posterity, as the building might not be there 50 years from when it was made.

The classical additions were usually made from terracotta as this was much easier to make than to carve the same elements out of stonework.