Over the years I've shot a fair number of weddings, and with the exception of the first couple I always used medium format C-41 film (Vericolour, and then Portra).
Mostly, I used a Mamiya C330. I have assisted however on weddings where the cameras were RB67s and Koni-Omegas (for the quick candids

!).
The 2nd to last wedding I shot was one where there was an official digital photographer, but I did a fairly full treatment as well. In that one I used both my C330, and a Mamiya 645.
It was a family wedding, and a couple of weeks after the fact my wife and I went over to the bride's parent's house where there was a casual party, with a whole bunch of the people who had been at the wedding. Everybody was looking at photos, that everyone had taken including the photos from the "official" photographers' photos, the 4x5 and 5x5
proofs I had had made, and a myriad of others shot by a bunch of the guests. Some of the others were from film (35mm) but the majority were digital.
The almost universal response to my proofs? - "they are so
clear and the colour is so
nice.
In my experience, even when the enlargements are small, there are visible benefits to using medium format or larger film.
Matt