Although receiving a familiar as a perk for newbies at the Judgment Court was beneficial, Dorothy could search the whole world for a familiar that suited her tastes.
However, this method was extremely inefficient, as she was ultimately not very familiar with this world, and searching for a needle in a haystack could take who knows how long.
If there was a recommendation from a local expert, particularly a seasoned Beastmaster who was well-acquainted with the Magical Beasts of this world, it would naturally be much easier for her to find a suitable familiar.
As the Female City Lord and the strongest Beastmaster in the Beast Taming World, Olivia, the Lord of the World, was naturally the person who knew this world the best.
Dorothy was never the type of witch who was stubborn or refused to heed other's advice; she preferred to analyze each situation carefully, and when facing unfamiliar matters, she was quite willing to listen to the advice of professionals.