4K is a higher resolution than 1080p, so a wedding film shot in 4K will have more detail and clarity than one shot in 1080p. This can make the film more engaging and immersive for the viewer, as they will be able to see more of the fine details and nuances of the event.
Additionally, a 4K film will have more visual information, which can be useful if the film needs to be edited or cropped in post-production. This can give the filmmaker more flexibility in how they approach the final cut of the film.
Finally, a 4K film will be able to take advantage of the latest display technologies, such as 4K TVs and projectors, which can provide an even more impressive viewing experience.