>>>What is she going to give them that they don't have already?<<<
Same thing Ryan Seacrest gives to iHeart Top 40 stations and Martha Quinn gives to iHeart Classic Hits stations. A better produced midday show than the local station would likely have, with a few celebrity interviews clips dropped in. And a way NOT to pay a midday DJ on your local station. (Yee's show will air live in middays after The Breakfast Club, not an afternoon show. WXKS-FM Boston actually runs Seacrest in the evening, although he's on middays in most markets.)
I suppose Angela Yee will air on iHeart Urban and Rhythmic stations outside the very biggest markets. And for other owners who enter into a syndication agreement with Premiere Networks for the show. iHeart is hoping to capitalize on the success of The Breakfast Club.