I know many people are paying high premiums for rare poured bars. Why not melt down some of your stack and pour your own bars? You would have a bar that is very rare, only 20 or so ever made...
Mintage is not the only factor. History as well. Engelhard bars have a long history. It is like comparing a Ferrari with a car you built in your garage. Sure the one you built is one of a kind (assuming you can even pull it off), but it will never have the pedigree of the Ferrari.
A lot of paintings are just paint sloshed on a canvas, some more skillfully than others. But at the end of the day it's still paint on a canvas. A digital watch is better at telling the time than an expensive automatic. Most cars get you from A to B. Most clothes cover you up and protect you. Is there any difference between them?