This guy sums it up perfectly from the Meguiar's forum:
*The coating used on automotive leather is semi permeable and can dry out if neglected. Cleaning is really important as dirt becomes embedded in the very fine pores and fissures in the coating and as you slide in and out of the car this actually amplifies the severity of contact with the surface, speeding up the wear on the coating which will reveal the colored leather underneath. That surface is very delicate and will degrade further really fast. A moisturizer will not only help prevent the whole leather/colorant/coating from drying out, it will act almost as a lubricant that helps slow down the effects of ingress and egress.*
It's like I always say. All automotive leather is coated, or else it would be destroyed upon first use. Automotive leather "breathes" on a microscopic level, that's why it's more comfortable and cooler to sit on than vinyl. I see newish cars who's leather is cracked, dried out, and destroyed because it wasn't maintained. The leather conditioners also preserve and protect the delicate stitching which vinyl "protectants" will destroy,which I've seen happen first hand.