I've read somewhere that it looked more "modern". This is from ISMACS regarding White's change to the crinkle finish...."
In the late 1920s, the company introduced the first-ever sewing machine
with a flat crinkle finish. The mark-resistant paint was supposed to be easier on the operator's eyes because it did not give off glare and was also more resilient to wear than the traditional japanned finish. In place of decalcomania decorations, fancy scrollwork was cast into the head of the machine. This kind of "modern" finish became popular in the late 1920s and 1930s, and other manufacturers, including Singer and National, followed with their own crinkled-finished machines but without the cast decorations."