Not to be trite or anything, but weddings are (almost) always happy occasions and a time to celebrate the joys of life. It is also a time when friends and family of the happy couple can join in with them and help them to celebrate their new life together. To this end, wedding blessings are a good way for you to show your happiness and to share your joy with everyone present.
Wedding blessings of course, is just another way to say “wedding toast” and generally runs along the same