Required at the end of music lesson too ... it's a gesture of respect to the instructor, and to practice for more formal performance. Ballet, absolutely, as well.
It's actually quite nice. The skaters line up, they make their bow/presentation/curtsey to the onlookers, parents, etc and then skate off; it signals the end of the session. However, remember, this is a private club, and these are not adult skaters, it ranges from 3 years on some sessions up to late teens. It's not public ice - I can see it being a bit of a head-scratcher if they did it on a public skate session
Thanking the coach is also a normal expectation, and, at comps, test days, etc, thanking all of the volunteers and officials.