is it really a pen name?

So Bernice McFadden, who I like, (check out The Warmest December), has penned a new book, called Groove under the pen name Geneva Holiday. When I visited her publisher's page though, this is what the bio says:

GENEVA HOLLIDAY is the alter ego of an acclaimed literary writer
who has penned five national bestsellers and been honored with the
Zora Neale Hurston Society Award, the Black Caucus ALA Literary Award,
the Black Writers Alliance Award, the Gold Pen Award, and the Barnes & Noble
Discover Great New Writers Award.

Okay, I know not everyone will know who it is, but come on.

I know authors do it ocassionally, like Omar Tyree and that alter ego he had, can't recall what is was, though. I mean if everywhere you look, promotional material says, Geneva Holliday aka Bernice McFadden, is it really a pen name? I guess I am wondering the pros and cons of using a new name when your real one works just fine.