Why do Glamour Play Shoes have an oval disck on the sole and on the heal of the shoe?

My 3 yo got this http://www.argos.co.uk/webapp/wcs/stores... glamour shows and they have plastic discs on the sole. I am worried she might lose her ballance and fall. Is there any reason they should be on the sole? Thank you.
Why do Glamour Play Shoes have an oval disck on the sole and on the heal of the shoe?
They give the shoes traction. I thought the same thing, but they never hindered my daughters princess-ness