Not only did this benefit the US in the sense that they began to expand even more AND they got super lucky with the amount of resources found in Alaska. BUT this was also super beneficial for the Russians: the creation of a stronger alliance between the two (until the Cold War but we don't need to talk about that) and the trade benefits that came from all of the resources within Alaska. AND at the time, Russia created a foothold over the British, who they just got out of the Crimean war with, since they cornered Canada with the US (who was slowly becoming a world superpower).