Photographing rings may not be the most exciting part of the wedding day, but it certainly is important. The symbolism of the rings, in a sense, is what led to the planning for the entire wedding day. If would be easy enough for a couple to agree to be married without rings, however tradition would suggest they are necessary to make such commitment official. As a result, including images of the couple's rings in their wedding album gives the images that follow a backstory.
The other reason it is important to photograph rings at a wedding is the fact they will, unfortunately, lose their shine and polish over time. The day of the wedding is when they will look the very best that they ever will, making these images a treasure for the couple to have as a keepsake.
Finally, as rings are very costly, it is nice for the couple to be able to really see the detail in the diamond cuts their invested to have created. So many times I hear brides exclaim that they did not realize the diamond corners were rounded, or the way tiny diamonds interlock. Seeing this clearly is exciting, and makes one appreciate their rings even more!