Why doesn't Baron Danglars want Eugenie to marry Albert De Morcef?

Danglars decides that he doesn't want Eugenie to marry Albert because he's set his sights on Andrea Cavalcanti. He notes that Fernand is not a true count, and thus, he prefers the Prince. Ironically, Cavalcanti is not a true Prince.... he is merely a thief, hired by the Count to play a part.... he does his job well.