I think tilt shift can be a fantastic creative tool at weddings, i
f used properly. I'd love to try it with diagonal group portrait arrangements and suchlike. Here's an example of tilt shift used to great effect, i.e. for diagonal plane of focus to get two subjects at different distances both in focus:
https://www.flickr.com/photos/carpeicthus/15470307803
What I personally cannot understand is people using an exotic and expensive lens for that cheap, everything-is-blurred-except-one-line-across-the-image effect that people can readily duplicate with their iPhone, and of course can easily be achieved in seconds in post with LR or PS.