Chein: Very, very few people have the authority to argue with R’ Moshe in America. In Eretz Yisroel there is more room to hold like someone else in major cases.
And Chacham: There are 24 volumes of the Tzitz Eliezer and a very high percentage of his T’shuvos are about medical issues. I don’t think it’s so much that he’s not quoted anywhere else as much as it is that he is never not quoted on these topics.