Hawaii was a good acquisition for the United States. A strong belief existed that world powers needed to protect their trade. This belief was based on Alfred Mahan’s book titled The Influence of Sea Power Upon History: 1660-1783. The United States was trying to become a world power at this time. Acquiring Hawaii would give us a presence in the Pacific Ocean. It would allow us to use Hawaii as a base from which we could station our navy and protect our trade. Hawaii could also be used as a military base in case of war.
The United States also had an economic interest in Hawaii. The sugar trade was very profitable for American sugar growers in Hawaii. When the Queen tried to reduce American influence in Hawaii, the sugar trade was threatened. The McKinley Tariff also hurt the Hawaiian sugar trade. After the Queen gave up power as a result of an uprising by the planters, American sugar growers in Hawaii wanted the United States to annex Hawaii so they could benefit from the favorable terms of the McKinley Tariff. This wouldn’t happen if the United States didn’t annex Hawaii.
Annexing Hawaii turned out to be a good move by the United States. Having a military base in the Pacific region helped us tremendously when we fought against Japan in World War II. The sugar trade also benefited the American economy.
The Hawaiian Islands were an ideal piece of real estate for a number of reasons. First, it's mid-Pacific location gave the U.S. a strong position to influence the growth of that particular economic sphere. As Japan and a number of European counties began expanding into the Pacific region, the U.S. needed a place beyond the shores of California to act a naval base in order to establish some sort of dominance in this region. Hawaii would eventually become the headquarters of the navy's department of the pacific after it was aquired.
Hawaii's agricultural wealth was also an important incentive for U.S. aquisiotion. The sugar industry on the islands was extreamly lucrative, and with a 1899 hurricane destroying much of Puerto Rico's sugar industry infastructure, Hawaii was even more of a money making venture.
For these reasons, the U.S. officially annexed Hawaii as a territory in 1897.