I disagree that there is “no reason”. I don’t think that is looking at the positive nature of it.
In the Sacrament of Baptism and Confirmation, there must be a witness of some kind that sponsors a person. THey stand up to say that they will support the person in their faith.
Marriage is so difficult to live out, why shouldn’t there be witnesses to do the same? I understand that canon law does not require it, however, perhaps in their marriage prep in the diocese/parish, the clergy are seeing this idea as something of value. Asking people around them to be actual stand up witnesses that this couple is ready for the sacrament, and say that they will support them in prayer as they live it out. Perhaps this is a way of lessening the divorce rate.
I know that if I ever get married, I will not have “bridesmaids”. They will not be up there to look pretty. They will be people that have been praying for us and challening us in our marriage prep, and people who will continue to be giving us support once married. They would be able to be asked if we are ready for the sacrament.