In actuality lining a holster with a soft leather like suede accelerates wear.
Leather soft or otherwise is not capable of wearing metal. What happens is that primer residue is transfered from the fired weapon to the leather and acts as an abrasive. Softer leathers trap and hold more of this residue so the wear will be somewhat quicker but inescapable in any case unless you never holster a weapon that you have fired.
A better way and one that is practical for lining a holster is to construct it of two pieces glued flesh side to flesh side. Say 4/5OZ glued to 5/6 or 7/8OZ so the grain or finished side is facing both inside and outside the holster. This makes for a firm and very durable holster.
Check out
www.leatherworker.net in the holster subforum for as much information as you could want.