Nike provides them, to do two things.
Here’s Nike’s ad regarding the WNBA. Especially beginning at 0:19, and most especially Nike’s closer, starting at 0:23.
The two things: continue not watching the WNBA, and not doing business with Nike (which company also does enthusiastic business with the genocide-committing People’s Republic of China, so here’s an additional reason for not doing business with Nike).
H/t Not the Bee