Objectivism regards the giving up of a greater value for a lesser one as being immoral. If, as a Christian, you value the life in the Spirit above the life of the flesh, then you will live up to those values.
Objectivism says that existence exists, and that reality cannot be ignored. Even Jesus did not ignore reality. He said that "You will always have the poor around you, but you will not always have me around". (Justifying the attention Mary Magdalene was giving him)
Sure, Rand's strict construction of Objectivism regards any spiritual inclination as "mysticism" and therefore immoral. I believe, however, that Objectivism is valuable for helping Christians prioritize matters of the flesh and matters of the spirit, and to realize that God may comfort you in bad times and forgive you your sins, but you're gonna have to bust your butt if you want that Lexus.
I think it adds an extra layer of complexity and doublespeak which should be unnecessary, but if it helps to convert a person from extreme selfishness, perhaps that's OK.
I can go for that.