Write endurance: Is there a difference between eMMC and Micro SD Card?
I can understand how write endurance is tied to this internal flash structure, but I don't think the write endurance has anything to do with whether there is an SD or eMMC interface on the front end.


The interface is determined by the controller the NAND cells are hooked up to, so putting an eMMC controller on a flash cell doesn't make it more reliable than if you'd hooked up an SD controller.  Each cell still has the same endurance, although different controllers can of course implement different wear leveling.  

The usual concern with SD cards however is the large number of fakes out there, which sometimes find their way into even legitimate products. In that sense, if you're buying higher endurance parts, it may be easier to find what you're looking for in an eMMC package or at least to be sure that your product has the part you think it does once it goes into production.