The initial purposes are distinct, of course. Weddings are to join two people as one, whereas funerals are send offs to people who are no longer with us. Where they tend to cross into each other every once in awhile is when the preachers turn the ceremonies into full out church services. This isn't relegated to one specific religion; off the shoulder wedding dresses it happens with almost any religion, and sometimes it's meant to mother of the bride dress be that way. Many times there's nothing wrong with a little "church"tossed into a ceremony; sometimes, though, it can be overwhelming, especially to those people who don't believe in the same faith and didn't know that's what they were coming for.
I have sat through both types of weddings. My own wedding took about 8 minutes, not including the time it took my bride to walk down the brief aisle; then again, I didn't get married in a church. On the flip side, I performed at a wedding once that took 2 1/2 hours. It was a Catholic wedding, and I sang 11 evening dresses songs. When the bride selected that many songs I was wondering what could be coming, and I got my answer. There is an understanding that sometimes a bride or groom wishes to honor their religion by adding elements of their religion to their wedding ceremony.
Nevertheless, I tend to be of the opinion that, though weddings are for the couple getting hitched, there needs to be some consideration for those who are coming to your ceremony. Not being Catholic, I'm not sure that I would have sat through a 2 1/2 hour ceremony if I hadn't been performing at it. When it comes to funerals, I'll often leave if it gets to 90 minutes and seems like it's going on longer. I did sit through a 90 minute wedding ceremony where the couple each had distinct religious backgrounds and thus the ceremony took on elements of both religions, but that was maternity wedding dresses a rare exception on my part, since it was friend's of my wife plus size wedding dresses with sleeves and not mine.