Continuity mistake: In the scene about the upcoming show the Baroness states she needs 12 key looks. She turns to count what she has and pulls down 10 looks that fill the board. When she turns back to face the staff she comments on the need for 10 looks.
Continuity mistake: At the Black and White party, when Cruella is taken to the Baroness, the position of Cruella's right hand has no continuity whatsoever in any of the shots.
Continuity mistake: When Horace exits the Black and White party, the amount of cake on his face is inconsistent between shots.
Answer: The Baroness probably thought that if she gave Estella's adoptive mother money and help that time, she would keep asking for more and more money under threat of revealing the secret that the Baroness was the girl's real mother. Killing her meant one less person who knew her secret and could hold it over her.
Sierra1 ★