Answer:
It serves as the gateway to the American continent and strategically for military purpose."
Step-by-step explanation:
The purpose of Spain in colonizing many territories in the American continents was to amassed wealth, particularly to explore golds and other valuable resources or minerals in the continent.
However, aside from the economic reason, the most important reason for Spain to colonize Puerto Rico for many centuries despite not having the wealth of the likes of Peru is that "it serves as the gateway to the American continent and strategically for military purpose."