Souper Salad's em dash

An em dash is an easy thing to misuse.  I think it resembles a pause or addition to people who are unaware of it's proper use. Before I knew how to use them, I would use em dashes as a sort of "um" in my paper.  I thought I was saying, "I just thought of this, so I'm adding it spontaneously to this sentence."

I think that Souper Salad used an em dash to emphasize that what they are saying is interesting.  The line "the first set is also used for defense" is not important to the overall message.  But Souper Salad is emphasizing the idea that they are crab specialists, so we better eat at their restaurant.