'Fresh' means new and inexperience and the service tends to be lower than what you could expect from an experienced staff.

As someone who worked in a restaurant, we had regulars that came to dine at our place 1-2 times a week and they would only come on the days that their favorite waiters were working and only wanted them to wait on them. The hostesses greeted these people by name and the bartenders could mix their drink to perfection. If you are constantly replacing staff you lose the ability to really get to know your customers and create an environment where they would want to return again and again.

You have a staff that rotates regularly, you lose that experience and familiarity that makes people want to return to your place again and again. With a casino, a player wants to return to their favorite dealers and see familiar faces. You keep replacing a staff like that the regulars will just go elsewhere for their business.

And this is Atlantic City, the training these people receive on the job at this place will help them get hired for permanent jobs in better casinos.