Think about it
If our enemies gain more land, resources, and wealth, then it'll be big trouble for England. We must get more land or else Britain would be a tiny, poor island country compared to other countries who explored the new world. And the possibility of a war would be imminent when our enemies gain the money and resources to do so. We can't let that happen so we must send expeditions of our own. And the possibilities that could be open for us, becoming a richer nation, more powerful, and much larger.