After speaking with a local shop, I believe a previous owner installed a wide glide conversion kit on my Dyna, what are the benefits or reasons for doing so? Dual rotors? Personal preference/flair?

 

Do you have the 41mm tubes?
If so he probably wanted to get rid of the 39mm tubes and get more rake angle to the front.
It's a personal preference thing. Some people think the 39mm front looks disproportionately small. Many also think they need more fork rake angle, for aesthetics.
There are no performance improvement benefits to the switch.

 

Benefit of a conversion kit is cost, you reuse your fork tubes and front wheel as opposed to a new complete front end