What are the implications of admitting a new state into the United States, but not extending US citizenship or extinguishing possessed foreign citizenship?

Section 19 of the Hawaii Admission Act and Section 21 of the Alaska Admission Act states: “Nothing contained in this Act shall operate to confer United States nationally heretofore, nor to terminate nationality heretofore lawfully acquired, or restore nationality heretofore lost under any law of the United States or under any treaty to which the […]