I think they are depending on the illiterate masses that just look at a picture and look at the price.
If you get 10 times the traffic of a well put together site with real text, but because of your lousy copy your conversion rate is 1/5, you are still getting twice as many sales.
It is the basic SPAM principal. Sening out 10,000,000 emails a day costs almost nothing, and you can turn a profit if you only sell to a fraction of 1%. Get high enough traffic and it doesn't matter that your conversion rate sucks.