You didn't really provide the letter out of which we should be able to deduce the benefits. However, Crusaders would say that the benefit of the crusaders were that they regained the holy land and could also profit out of this either by looting and pillaging neighbouring muslim villages or because they thought they were closer to God this way.
Explanation: The letter does not mention anything in regard to the loyalty the crusader had for his country. It also does not talk about the love of battle. However, the letter talks about the devotion to God he felt. The crusader says that God has brought him his prosperity and safety, and he feels happy to be nearing the "home of our Lord." He also discusses wealth, as he says he now has twice as much gold, silver and other riches that he will bring home.
The Puritans of Massachusetts hoped to create a self-governing religious community that would have very strong bounds between the people and be tightly-knit.