The definition of "leather" as made by some manufacturers can be rather dubious. The text sometimes being accompanied by a very small asterisk which advises you of what you are actually buying. A bit like "fruit juice" and "juice drinks". I am aware of one Far East car manufacturer who ended up paying damages for misrepresentation.
With regular feeding, good leather should be extremely durable as long as the tanning and colouring is carried out correctly. Picture shows the seats of my 4/4 when it was around ten years old and approximately 35k miles - still looking good today.
