I can see how the ugly ad could get more clicks. It looks so different from everything else that you're naturally curious to see what it leads to.

I will also add that the "professionally designed" ad is kind of busy. It has so many things going on (some text in all caps, different colors, some quoted, illustration doesn't add much value, arrows that don't mean anything) that it doesn't really catch your attention or call you to action. The "ugly" ad, however, gets to the point.