Why was it sprinkled with sesame?

On my first visit I found something in my fried rice but I decided to give it a revisit.
It seems that I was not the only one to find something, ChanJan also found an ant in the drink!

This time I did not find anything extra however I was given an extra topping!

I ordered the fish shaomai which was from their steamer, as with all fish shaomai they put chili oil/sauce or soy sauce on it and the dark red sauce that is used for rice rolls if you ask for it.
Anyway, he asked me if I wanted soy sauce and chili sauce so I said Yes so I was just expecting those two, but before I could even stop him, he had already sprinkled sesame seeds on the fish shaomai.

I have never seen any other shop sprinkle sesame seeds on fish shaomai but only on rice rolls from my experience.

As the taste, the fish shaomai were not hot enough, the sauce was quite nice apart from the sesame seeds.
Although the sauce was plain soy sauce and chili, it had other sauces mixed in which I hope wasnt left over sauces from other stuff!

The price was really expensive as well, usually fish shaomai ranges from $10 to $12 but here it costs $16 not including a drink.