Answer:
To get support and sponsored for more voyages and exploration.
Step-by-step explanation:
The significance of Christopher Columbus's first letter from the Americas was to get the attention of the audience of European officials and merchants, specifically the Catholic monarchs, in King Ferdinand and Queen Isabella of Spain, so he could hopefully get sponsored for more voyages and exploration.
With a keen interest for economic opportunities, Columbus in his first letter, fully point out potential economic gain to make his voyage appear a success.
Columbus emphasizes the masses of new souls available and inclined for conversion to Catholic Christianity