Why Is This Coin So Popular

The normal mintage of a $1 circulating coin is in the millions, with most commemorative coins from the Royal Australian Mint around a mintage of 30,000 to 50,000 and this is what makes this particular coin popular.  The 2015 $1 WWI War Heroes coin with the red poppy on the obverse has a very low mintage, in fact one of the lowest mintages of any $1 coin produced by RAM with only 13,500 minted.  This coin will remain very collectable and I can not see the price dropping in the near future with the still fetching as high as $150 or more in the market.