Benefited them by serving as a mean of transportation for Native Americans. With horses the Natives could hunt more food like buffalo more easily. Horses also helped strengthen their military.
When the Europeans arrived in the "New World" the Natives were exposed to new diseases they have never dealt with before. One of these diseases was The Smallpox. These diseases helped the Europeans take over in the way, that since most of population was dying because of all the diseases.
The Natives were forced to convert into Christianity. The Europeans would punish or even kill Natives that refused to convert. Many Natives converted willingly to avoid being killed. Other Natives tried to escape, some were captured and killed. The Europeans believed that the Natives were dying out because God was punishing them, but they didn't realize that the diseases that they brought was actually killing them.
When sugar was discovered everyone wanted some. With some many requests for sugar someone had to plant and cared for it. This led to slavery.
The Europeans forced the Natives into slavery to tend sugar can plantations.
Some crops traded were barley, sugar, potato, wheat,maize (corn), cofee caca