I was looking to some examples of the use of 人 and I found this one in Jisho.org
Two hundred people died of cholera last year.
With furigana for the first case にん and for the second ひと. So I was trying to guess why is the kanji repeated and I thought that probably it was due to the need to indicate what were you counting. But then, wasn't supposed that ～ニン implies that you are counting people?