Also - note how the furniture in the "after" is nicer, so it also sends the message that if you get the sewing machine, you've moved up a rung on the social ladder.
So many of them even show the people looking much coarser in the "before" compared to the "after" -
I do like the "picture within a picture" look though - with the first picture being the "picture" on the wall in the second picture . . .