Out of the 613 commandments, it's undoubtedly true that most people are sinners guilty of stoning in 1st century Judea. Society has changed, as have most Christians. I think we should also question the Bible's veracity -- given the number of edited, translated, and mistranslated scrolls and texts that eventually became the Bible. This shouldn't be a thorn in the Church's side -- if God gave you a rational brain to understand the world; using it shouldn't be a sin. Rather -- either the Holy Book is wrong or it was meant to be interpreted differently.
The advantage for the church to accept evolution is that they will achieve more credibility in the eyes of the younger generations. Churches cling to outdated ideas for far too long in many cases. Many modern clergy have suggested that the bible leaves room interpretation of how long in human years a day really is to God. It is time the church gave full support to modern theory and allow it to blend with scientific theory.
I do not believe there are advantages for the church if it accepts evolution because The Bible is clear on creationism. If the church accepts evolution, they are admitting that a part of The Bible must be wrong and in turn they are harming the credibility of The Bible as a whole. If one part is wrong, that opens the door for other parts being wrong as well.