In the Arch-diocese of Chicago, we have received directions to bow as a sign of reverence prior to receiving the eucharist.
One of the reasons given, presented by the pastor at all masses one weekend, was for unity. As opposed to one person kneeling, one bowing, one genuflecting, or whatever else.
My understanding is that this is for all of the church, but the bishop of the diocese is to determine when it is implemented.
I used to make the sign of the cross prior to receiving the eucharist myself. Now, I really like the bow. It helps me in humility - to understand where I stand before God.