Sophie Turner and Joe Jonas's unexpected wedding was a surprise to everyone, as both said earlier that "they are planning a wedding this summer in France". According to People, weddings in France will take place during the summer and the ceremony in Las Vegas was simply to make their marriage legal.
In France, a legal or religious marriage does not constitute legal marriage, both of which were married in advance to the US.
This means that Maisie Williams (Sophie's close friend and bride's companion) will have her special moment at the next wedding in France.