I wouldn't be surprised to find that some measurable percentage of "official person tasked with photographing a wedding" are just using phones. These are not professional wedding photographers, but they are acting as a wedding photographer while using a phone camera. (And they are friends or family doing the task for free.)
Surely many weddings are not high expenditure events. An average person with a modern phone who takes a LOT of photos at each moment or scene will produce some good images. They may not be of the quality where you could print large poster size, but most people probably don't print larger than 11x14.
There's no doubt that a skilled photographer with good gear that is suited for the environment can do better. Phones are not a replacement for this if final result is the only criteria. But not only are not all "professional" photographers great, but a lucky amateur with a good phone cam and lots of snaps may end up with output that a layperson, including the subjects of the wedding, might not be able to see the difference of.