It depends on what you define as "genocide."

Some historians such as Howard Zinn would contend that the systemic removal, forced relocation, and often deliberate massacring of Native Americans during the 19th century constituted "genocide."

I don't feel entirely comfortable with the label of genocide in that instance because:

1. That viewpoint tends to treat Native Americans as one monolithic minority group, when in reality there were vast differences between tribes. The Comanche and the Cherokee are both "Native Americans" but their cultures could not be further apart. The Comanche in particular were absolutely brutal toward settlers and other tribes, they were terrible stewards of their environment, and their nomadic culture gave them quite an absurdly entitled view of what constituted "their land." The Cherokee on the other hand were generally peaceful, practiced sustainable agriculture, and were open to trade with settlers. My point is that we shouldn't lump all Native Americans into one group, nor should we treat US government policy against them as wholly morally unjustified (to be clear, most of it was, but it is more nuanced than that).

2. While the forced relocation of Native Americans systemically occurred, the ways in which tribal populations were wiped out were not always explicitly deliberate and were often the result of a lot of compounding factors. Typically we think of genocides as being carried out swiftly over the course of a few months to a few years by a single administration or government with the malicious goal of erasing a group of people out of existence. While malice certainly played a role in the historical mistreatment of Native Americans, there was also a lot of ignorance and incompetence on the part of the government that resulted in terrible outcomes (e.g., the government relocates a tribe a thousand miles away to somewhere in Oklahoma and doesn't anticipate that a particularly bad winter will wipe half of them out by the time they get there.)

The United States believed that its westward expansion was threatened by the warring western Plains Indians, as they would regularly raid and pillage white settlements. It didn't help that the United States had also forcibly removed the generally peaceful tribes in the southeast under the Indian Removal Act of 1830 and relocated them to the midwest, where the western Plains Indians roamed. The confluence of settlers and tribes in the midwest and west resulted in a lot of bloodshed on all sides due to the sheer competition for what limited resources there were west of the Mississippi.

All of this leads me back to your original question. Whether we call it genocide or not, what happened to the Native Americans was arguably inevitable. If it hadn't been the Americans who did it, it would have been the British, Russians, or Spanish, all of whom were expanding their territorial reach in what is now the western United States. While the United States was pushing westward, the Russians were pushing south from Alaska (they even had a settlement in California in the 1800s), the British were creeping southward into Oregon from British Columbia, and Spain was pushing northward from Mexico.

So there's little doubt that the United States benefitted tremendously from, depending on how you look at it, "westward expansion" or the "genocide" of Native Americans. Ensuring that Americans could enjoy relatively safe passage from the east coast to the west coast by the end of the 19th century prompted an economic boom as it opened up the Pacific coast to trade and immigration. It set the stage for the United States to become an economic and military superpower by providing two extensive coastlines that could deter any foreign invasion while also facilitating global trade. If the United States did not control both coastlines, I think the world of today would look incredibly different.

TL;DR: The American government's westward expansion and the relocation and subsequent decimation of the Native American tribes that came with it - which some consider to be genocide - gave the United States a huge territorial advantage that would greatly benefit the country in the 20th century.

Sources:

Diamond, Jared. Guns, Germs, and Steel: The Fates of Human Societies.

Gwynne, S.G. Empire of the Summer Moon: Quanah Parker and the Rise and Fall of the Comanches, the Most Powerful Indian Tribe in American History.

Zinn, Howard. A People's History of the United States.

Edit: Please see my second comment in response to my sourcing of Zinn and Diamond. Since this is /r/askhistorians, I would appreciate it if people who are downvoting me would explain why.