The English objectives of colonization depended on which sector of the population was defining them.
For the government in general, the advantage of colonization was having more land, and in particular, fertile, productive land. Another advantage of having more land is the fact that land gives extra power. It allows you to have a larger army and navy. It also provides prestige. Finally, wealth in the form of natural resources and trade was a powerful motivator.
Priests, educators and the upper classes involved in charity work believed colonization to be humanitarian. They wanted to educate "savages" so that they could be more cultured, lived in a more civilized way, and followed the "correct" religion.
For many individuals, the main objective of discovering and acquiring new land was adventure, and discovery. Colonization came with exploration, and many scientific advancements were produced due to the enormous territories that the United Kingdom acquired and studied.
As for whether this enterprise was successful in achieving those goals, for the most part it appears like it was. Wealth greatly increased in England, and they did become a superpower. The empire also "reeducated" millions of people around the world and achieved great feats of adventure and discovery.
