Chaz Bono can do something as a man which she could never do as a woman in California -- marry her partner.
At a point during the gender change -- typically when breasts are removed -- the subject can go to court and ask a judge to legally change his/her sex. It's discretionary on the part of the judge in determining when the person switches sex and is entitled to a legal change, but typically it's when the breasts are removed.
Judges typically do not require a genitalia switch as a prerequisite to a sex change.
Chaz has been in a committed relationship for several years. Therefore, what Chaz could never do now -- marry his partner -- he can do when the law acknowledges he is indeed a he.
Exact same person -- totally different result. Go figure.