How much advantage in adding rear disk brakes?

My 2000 Dakota R/T didn't need rear shoes until almost 100,000 miles!
Many of those miles were either "spirited" or hauling or towing something.
During that time I think I put on three sets of front pads and 2 sets of rotors.

I'm glad AJFormS mentioned wheel cylinder sizes as I'm entirely convinced that's how the factory achieved "proportioning" rather than with a valve like you read about so often.

I've seen a LOT of people not touch the adjusters when doing rear shoes.
I always inspect them, lube them inside and out, replace them if they bind, and manually activate them by pulling the cable to verify operation. Routing that cable correctly is crucial as well.