As I stated before, you could apply this to ANY comic. The general public simply doesn't know if there are boxes in a warehouse, how many file copies, etc...
For instance, I recently purchased the first prototype of a popular independent character for below market value. Why was it below market? The comic itself has multiple stories in it. One of the creators of one of the other characters that didn't take off had a case of the issue in their closet. Obviously for personal reasons. They leaked out about 10-15 this time. What is considered scarce, low print, hard to find etc... is all relative to the market at any given time. This is not unique to variants.